diff --git a/GitCommands/Config/ConfigFile.cs b/GitCommands/Config/ConfigFile.cs
index 833f1d2a1eb..821ed9c7566 100644
--- a/GitCommands/Config/ConfigFile.cs
+++ b/GitCommands/Config/ConfigFile.cs
@@ -10,16 +10,16 @@ namespace GitCommands.Config
 {
     public class ConfigFile
     {
-        public string FileName { get; }
+        private readonly List<IConfigSection> _configSections = new List<IConfigSection>();
 
+        public string FileName { get; }
         public bool Local { get; }
 
         public ConfigFile(string fileName, bool local)
         {
-            ConfigSections = new List<IConfigSection>();
             Local = local;
-
             FileName = fileName;
+
             try
             {
                 Load();
@@ -31,7 +31,7 @@ public ConfigFile(string fileName, bool local)
             }
         }
 
-        public IList<IConfigSection> ConfigSections { get; }
+        public IReadOnlyList<IConfigSection> ConfigSections => _configSections;
 
         public IEnumerable<IConfigSection> GetConfigSections(string sectionName)
         {
@@ -214,7 +214,7 @@ public string GetPathValue(string setting)
             return GetStringValue(setting);
         }
 
-        public IList<string> GetValues(string setting)
+        public IReadOnlyList<string> GetValues(string setting)
         {
             var keyIndex = FindAndCheckKeyIndex(setting);
 
@@ -249,7 +249,7 @@ public IConfigSection FindOrCreateConfigSection(string name)
             if (result == null)
             {
                 result = new ConfigSection(name, true);
-                ConfigSections.Add(result);
+                _configSections.Add(result);
             }
 
             return result;
@@ -262,7 +262,7 @@ public void AddConfigSection(IConfigSection configSection)
                 throw new ArgumentException("Can not add a section that already exists: " + configSection.SectionName);
             }
 
-            ConfigSections.Add(configSection);
+            _configSections.Add(configSection);
         }
 
         public void RemoveConfigSection(string configSectionName)
@@ -274,7 +274,7 @@ public void RemoveConfigSection(string configSectionName)
                 return;
             }
 
-            ConfigSections.Remove(configSection);
+            _configSections.Remove(configSection);
         }
 
         public IConfigSection FindConfigSection(string name)
@@ -336,7 +336,7 @@ private void NewSection()
                 if (_section == null)
                 {
                     _section = new ConfigSection(sectionName, false);
-                    _configFile.ConfigSections.Add(_section);
+                    _configFile._configSections.Add(_section);
                 }
             }
 
diff --git a/GitCommands/Config/ConfigSection.cs b/GitCommands/Config/ConfigSection.cs
index 06d95a67903..865ba1ee760 100644
--- a/GitCommands/Config/ConfigSection.cs
+++ b/GitCommands/Config/ConfigSection.cs
@@ -18,11 +18,11 @@ namespace GitCommands.Config
     /// </summary>
     public class ConfigSection : IConfigSection
     {
-        private readonly IDictionary<string, IList<string>> _configKeys;
+        private readonly IDictionary<string, List<string>> _configKeys;
 
         internal ConfigSection(string name, bool forceCaseSensitive)
         {
-            _configKeys = new Dictionary<string, IList<string>>(StringComparer.OrdinalIgnoreCase);
+            _configKeys = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
 
             if (name.Contains("\""))
             {
@@ -73,9 +73,9 @@ public static string FixPath(string path)
             return path.ToPosixPath();
         }
 
-        public IDictionary<string, IList<string>> AsDictionary()
+        public IDictionary<string, IReadOnlyList<string>> AsDictionary()
         {
-            return _configKeys.ToDictionary(kv => kv.Key, kv => kv.Value, StringComparer.OrdinalIgnoreCase);
+            return _configKeys.ToDictionary(kv => kv.Key, kv => (IReadOnlyList<string>)kv.Value, StringComparer.OrdinalIgnoreCase);
         }
 
         public bool HasValue(string key)
@@ -128,7 +128,7 @@ public string GetValue(string key, string defaultValue)
             return defaultValue;
         }
 
-        public IList<string> GetValues(string key)
+        public IReadOnlyList<string> GetValues(string key)
         {
             return _configKeys.ContainsKey(key) ? _configKeys[key] : new List<string>();
         }
diff --git a/GitCommands/ExternalLinks/ConfiguredLinkDefinitionsProvider.cs b/GitCommands/ExternalLinks/ConfiguredLinkDefinitionsProvider.cs
index c72704d7906..1258b8c0d38 100644
--- a/GitCommands/ExternalLinks/ConfiguredLinkDefinitionsProvider.cs
+++ b/GitCommands/ExternalLinks/ConfiguredLinkDefinitionsProvider.cs
@@ -13,7 +13,7 @@ public interface IConfiguredLinkDefinitionsProvider
         /// <summary>
         /// Loads all persisted external link definitions across all setting layers.
         /// </summary>
-        IList<ExternalLinkDefinition> Get(RepoDistSettings settings);
+        IReadOnlyList<ExternalLinkDefinition> Get(RepoDistSettings settings);
     }
 
     /// <summary>
@@ -31,7 +31,7 @@ public ConfiguredLinkDefinitionsProvider(IExternalLinksLoader externalLinksLoade
         /// <summary>
         /// Loads all persisted external link definitions across all setting layers.
         /// </summary>
-        public IList<ExternalLinkDefinition> Get(RepoDistSettings settings)
+        public IReadOnlyList<ExternalLinkDefinition> Get(RepoDistSettings settings)
         {
             if (settings == null)
             {
diff --git a/GitCommands/ExternalLinks/ExternalLinkRevisionParser.cs b/GitCommands/ExternalLinks/ExternalLinkRevisionParser.cs
index ea330a3fd66..310c9bdda13 100644
--- a/GitCommands/ExternalLinks/ExternalLinkRevisionParser.cs
+++ b/GitCommands/ExternalLinks/ExternalLinkRevisionParser.cs
@@ -45,7 +45,7 @@ private static IEnumerable<GitRemote> GetMatchingRemotes(ExternalLinkDefinition
 
         private IEnumerable<Match> ParseRemotes(ExternalLinkDefinition definition)
         {
-            IList<Match> allMatches = new List<Match>();
+            var allMatches = new List<Match>();
 
             if (definition.RemoteSearchPattern.IsNullOrWhiteSpace() || definition.RemoteSearchPatternRegex.Value == null)
             {
@@ -53,7 +53,7 @@ private IEnumerable<Match> ParseRemotes(ExternalLinkDefinition definition)
                 return allMatches;
             }
 
-            IList<string> remoteUrls = new List<string>();
+            var remoteUrls = new List<string>();
 
             var remotes = _gitRemoteManager.LoadRemotes(false);
             var matchingRemotes = GetMatchingRemotes(definition, remotes);
@@ -128,7 +128,7 @@ private static IEnumerable<ExternalLink> ParseRevisionPart(GitRevision revision,
                 yield break;
             }
 
-            IList<Match> allMatches = new List<Match>();
+            var allMatches = new List<Match>();
 
             MatchCollection matches = definition.SearchPatternRegex.Value.Matches(part);
             for (var i = 0; i < matches.Count; i++)
diff --git a/GitCommands/ExternalLinks/ExternalLinksLoader.cs b/GitCommands/ExternalLinks/ExternalLinksLoader.cs
index 9aefd9527a8..fa6e4c14473 100644
--- a/GitCommands/ExternalLinks/ExternalLinksLoader.cs
+++ b/GitCommands/ExternalLinks/ExternalLinksLoader.cs
@@ -14,12 +14,12 @@ public interface IExternalLinksLoader
         /// <summary>
         /// Loads external link definitions from the settings.
         /// </summary>
-        IList<ExternalLinkDefinition> Load(RepoDistSettings settings);
+        IReadOnlyList<ExternalLinkDefinition> Load(RepoDistSettings settings);
 
         /// <summary>
         /// Saves the provided external link definitions to the settings.
         /// </summary>
-        void Save(RepoDistSettings settings, IList<ExternalLinkDefinition> definitions);
+        void Save(RepoDistSettings settings, IReadOnlyList<ExternalLinkDefinition> definitions);
     }
 
     public sealed class ExternalLinksLoader : IExternalLinksLoader
@@ -29,7 +29,7 @@ public sealed class ExternalLinksLoader : IExternalLinksLoader
         /// <summary>
         /// Loads external link definitions from the settings.
         /// </summary>
-        public IList<ExternalLinkDefinition> Load(RepoDistSettings settings)
+        public IReadOnlyList<ExternalLinkDefinition> Load(RepoDistSettings settings)
         {
             var cachedSettings = new RepoDistSettings(null, settings.SettingsCache);
             var xml = cachedSettings.GetString(SettingName, null);
@@ -39,7 +39,7 @@ public IList<ExternalLinkDefinition> Load(RepoDistSettings settings)
         /// <summary>
         /// Saves the provided external link definitions to the settings.
         /// </summary>
-        public void Save(RepoDistSettings settings, IList<ExternalLinkDefinition> definitions)
+        public void Save(RepoDistSettings settings, IReadOnlyList<ExternalLinkDefinition> definitions)
         {
             try
             {
@@ -68,7 +68,7 @@ public void Save(RepoDistSettings settings, IList<ExternalLinkDefinition> defini
         }
 
         // TODO: refactor and outsource to the centralised SettingsSerialiser implementations.
-        private static IList<ExternalLinkDefinition> LoadFromXmlString(string xmlString)
+        private static IReadOnlyList<ExternalLinkDefinition> LoadFromXmlString(string xmlString)
         {
             if (string.IsNullOrWhiteSpace(xmlString))
             {
diff --git a/GitCommands/ExternalLinks/ExternalLinksManager.cs b/GitCommands/ExternalLinks/ExternalLinksManager.cs
index 72307a1a2ef..808943768ae 100644
--- a/GitCommands/ExternalLinks/ExternalLinksManager.cs
+++ b/GitCommands/ExternalLinks/ExternalLinksManager.cs
@@ -11,12 +11,12 @@ public sealed class ExternalLinksManager
         private readonly RepoDistSettings _cachedSettings;
         private readonly ExternalLinksManager _lowerPriority;
         private readonly IExternalLinksLoader _externalLinksLoader = new ExternalLinksLoader();
-        private readonly IList<ExternalLinkDefinition> _definitions;
+        private readonly List<ExternalLinkDefinition> _definitions;
 
         public ExternalLinksManager(RepoDistSettings settings)
         {
             _cachedSettings = new RepoDistSettings(null, settings.SettingsCache);
-            _definitions = _externalLinksLoader.Load(_cachedSettings);
+            _definitions = _externalLinksLoader.Load(_cachedSettings).ToList();
 
             if (settings.LowerPriority != null)
             {
@@ -64,10 +64,11 @@ public bool Contains(string definitionName)
         /// Loads all settings from all available levels.
         /// </summary>
         /// <returns>A collection of all available definitions.</returns>
-        public IList<ExternalLinkDefinition> GetEffectiveSettings()
+        public IReadOnlyList<ExternalLinkDefinition> GetEffectiveSettings()
         {
-            var effective = _definitions.Union(_lowerPriority?.GetEffectiveSettings() ?? Enumerable.Empty<ExternalLinkDefinition>()).ToList();
-            return effective.ToList();
+            return _definitions
+                .Union(_lowerPriority?.GetEffectiveSettings() ?? Enumerable.Empty<ExternalLinkDefinition>())
+                .ToList();
         }
 
         /// <summary>
diff --git a/GitCommands/Git/GitCommandHelpers.cs b/GitCommands/Git/GitCommandHelpers.cs
index 0e874ad2fb9..9033792787a 100644
--- a/GitCommands/Git/GitCommandHelpers.cs
+++ b/GitCommands/Git/GitCommandHelpers.cs
@@ -1095,7 +1095,7 @@ public static GitSubmoduleStatus GetSubmoduleStatus(string text, GitModule modul
         /*
                source: https://git-scm.com/docs/git-status
         */
-        public static List<GitItemStatus> GetAllChangedFilesFromString(IGitModule module, string statusString, bool fromDiff = false)
+        public static IReadOnlyList<GitItemStatus> GetAllChangedFilesFromString(IGitModule module, string statusString, bool fromDiff = false)
         {
             var diffFiles = new List<GitItemStatus>();
 
@@ -1130,7 +1130,7 @@ The file will have its original line endings in your working directory.*/
             }
 
             // Doesn't work with removed submodules
-            IList<string> submodules = module.GetSubmodulesLocalPaths();
+            var submodules = module.GetSubmodulesLocalPaths();
 
             // Split all files on '\0' (WE NEED ALL COMMANDS TO BE RUN WITH -z! THIS IS ALSO IMPORTANT FOR ENCODING ISSUES!)
             var files = trimmedStatus.Split(new[] { '\0' }, StringSplitOptions.RemoveEmptyEntries);
diff --git a/GitCommands/Git/GitGpgController.cs b/GitCommands/Git/GitGpgController.cs
index f5030dadbd9..891d0c68eab 100644
--- a/GitCommands/Git/GitGpgController.cs
+++ b/GitCommands/Git/GitGpgController.cs
@@ -230,7 +230,7 @@ private string GetTagVerificationMessage(IGitRef tagRef, bool raw = true)
             return module.RunGitCmd($"verify-tag {rawFlag} {tagName}");
         }
 
-        private string EvaluateTagVerifyMessage(IList<IGitRef> usefulTagRefs)
+        private string EvaluateTagVerifyMessage(IReadOnlyList<IGitRef> usefulTagRefs)
         {
             if (usefulTagRefs.Count == 0)
             {
diff --git a/GitCommands/Git/GitModule.cs b/GitCommands/Git/GitModule.cs
index 8c5174efc45..26ca9b03bcd 100644
--- a/GitCommands/Git/GitModule.cs
+++ b/GitCommands/Git/GitModule.cs
@@ -445,7 +445,7 @@ public bool HasSubmodules()
         /// This approach is a faster than <see cref="GetSubmodulesInfo"/> which
         /// invokes the <c>git submodule</c> command.
         /// </remarks>
-        public IList<string> GetSubmodulesLocalPaths(bool recursive = true)
+        public IReadOnlyList<string> GetSubmodulesLocalPaths(bool recursive = true)
         {
             var submodules = GetSubmodulePaths(this);
 
@@ -958,7 +958,7 @@ public List<ConflictData> GetConflicts(string filename = "")
             return list;
         }
 
-        public IList<string> GetSortedRefs()
+        public IReadOnlyList<string> GetSortedRefs()
         {
             const string command = "for-each-ref --sort=-committerdate --sort=-taggerdate --format=\"%(refname)\" refs/";
 
@@ -1903,7 +1903,7 @@ public string ApplyPatch(string dir, string amCommand)
             }
         }
 
-        public string AssumeUnchangedFiles(IList<GitItemStatus> files, bool assumeUnchanged, out bool wereErrors)
+        public string AssumeUnchangedFiles(IReadOnlyList<GitItemStatus> files, bool assumeUnchanged, out bool wereErrors)
         {
             var output = "";
             string error = "";
@@ -1927,7 +1927,7 @@ public string AssumeUnchangedFiles(IList<GitItemStatus> files, bool assumeUnchan
             return output.Combine(Environment.NewLine, error);
         }
 
-        public string SkipWorktreeFiles(IList<GitItemStatus> files, bool skipWorktree)
+        public string SkipWorktreeFiles(IReadOnlyList<GitItemStatus> files, bool skipWorktree)
         {
             var output = "";
             string error = "";
@@ -1950,7 +1950,7 @@ public string SkipWorktreeFiles(IList<GitItemStatus> files, bool skipWorktree)
             return output.Combine(Environment.NewLine, error);
         }
 
-        public string StageFiles(IList<GitItemStatus> files, out bool wereErrors)
+        public string StageFiles(IReadOnlyList<GitItemStatus> files, out bool wereErrors)
         {
             var output = "";
             string error = "";
@@ -1991,7 +1991,7 @@ public string StageFiles(IList<GitItemStatus> files, out bool wereErrors)
             return output.Combine(Environment.NewLine, error);
         }
 
-        public string UnstageFiles(IList<GitItemStatus> files)
+        public string UnstageFiles(IReadOnlyList<GitItemStatus> files)
         {
             var output = "";
             string error = "";
@@ -2092,12 +2092,12 @@ public bool InTheMiddleOfInteractiveRebase()
             return File.Exists(GetRebaseDir() + "git-rebase-todo");
         }
 
-        public IList<PatchFile> GetInteractiveRebasePatchFiles()
+        public IReadOnlyList<PatchFile> GetInteractiveRebasePatchFiles()
         {
             string todoFile = GetRebaseDir() + "git-rebase-todo";
             string[] todoCommits = File.Exists(todoFile) ? File.ReadAllText(todoFile).Trim().Split(new[] { '\n', '\r' }, StringSplitOptions.RemoveEmptyEntries) : null;
 
-            IList<PatchFile> patchFiles = new List<PatchFile>();
+            var patchFiles = new List<PatchFile>();
 
             if (todoCommits != null)
             {
@@ -2131,7 +2131,7 @@ public IList<PatchFile> GetInteractiveRebasePatchFiles()
             return patchFiles;
         }
 
-        public IList<PatchFile> GetRebasePatchFiles()
+        public IReadOnlyList<PatchFile> GetRebasePatchFiles()
         {
             var patchFiles = new List<PatchFile>();
 
@@ -2365,7 +2365,7 @@ public void SetPathSetting(string setting, string value)
             LocalConfigFile.SetPathValue(setting, value);
         }
 
-        public IList<GitStash> GetStashes()
+        public IReadOnlyList<GitStash> GetStashes()
         {
             var list = RunGitCmd("stash list").Split('\n');
 
@@ -2456,19 +2456,19 @@ public string GetDiffFilesText(string firstRevision, string secondRevision, bool
             return noCache ? RunGitCmd(cmd) : RunCacheableCmd(AppSettings.GitCommand, cmd, SystemEncoding);
         }
 
-        public List<GitItemStatus> GetDiffFilesWithSubmodulesStatus(string firstRevision, string secondRevision)
+        public IReadOnlyList<GitItemStatus> GetDiffFilesWithSubmodulesStatus(string firstRevision, string secondRevision)
         {
             var status = GetDiffFiles(firstRevision, secondRevision);
             GetSubmoduleStatus(status, firstRevision, secondRevision);
             return status;
         }
 
-        public List<GitItemStatus> GetDiffFiles(string firstRevision, string secondRevision, bool noCache = false)
+        public IReadOnlyList<GitItemStatus> GetDiffFiles(string firstRevision, string secondRevision, bool noCache = false)
         {
             noCache = noCache || firstRevision.IsArtificial() || secondRevision.IsArtificial();
             string cmd = DiffCommandWithStandardArgs + "-M -C -z --name-status " + _revisionDiffProvider.Get(firstRevision, secondRevision);
             string result = noCache ? RunGitCmd(cmd) : RunCacheableCmd(AppSettings.GitCommand, cmd, SystemEncoding);
-            var resultCollection = GitCommandHelpers.GetAllChangedFilesFromString(this, result, true);
+            var resultCollection = GitCommandHelpers.GetAllChangedFilesFromString(this, result, true).ToList();
             if (firstRevision == GitRevision.UnstagedGuid || secondRevision == GitRevision.UnstagedGuid)
             {
                 // For unstaged the untracked must be added too
@@ -2492,9 +2492,9 @@ public List<GitItemStatus> GetDiffFiles(string firstRevision, string secondRevis
             return resultCollection;
         }
 
-        public IList<GitItemStatus> GetStashDiffFiles(string stashName)
+        public IReadOnlyList<GitItemStatus> GetStashDiffFiles(string stashName)
         {
-            var resultCollection = GetDiffFiles(stashName + "^", stashName, true);
+            var resultCollection = GetDiffFiles(stashName + "^", stashName, true).ToList();
 
             // shows untracked files
             string untrackedTreeHash = RunGitCmd("log " + stashName + "^3 --pretty=format:\"%T\" --max-count=1");
@@ -2507,7 +2507,7 @@ public IList<GitItemStatus> GetStashDiffFiles(string stashName)
             return resultCollection;
         }
 
-        public IList<GitItemStatus> GetTreeFiles(string treeGuid, bool full)
+        public IReadOnlyList<GitItemStatus> GetTreeFiles(string treeGuid, bool full)
         {
             var tree = GetTree(treeGuid, full);
 
@@ -2536,12 +2536,12 @@ public IList<GitItemStatus> GetTreeFiles(string treeGuid, bool full)
             return list;
         }
 
-        public IList<GitItemStatus> GetAllChangedFiles(bool excludeIgnoredFiles = true,
+        public IReadOnlyList<GitItemStatus> GetAllChangedFiles(bool excludeIgnoredFiles = true,
             bool excludeAssumeUnchangedFiles = true, bool excludeSkipWorktreeFiles = true,
             UntrackedFilesMode untrackedFiles = UntrackedFilesMode.Default)
         {
             var status = RunGitCmd(GitCommandHelpers.GetAllChangedFilesCmd(excludeIgnoredFiles, untrackedFiles));
-            List<GitItemStatus> result = GitCommandHelpers.GetAllChangedFilesFromString(this, status);
+            var result = GitCommandHelpers.GetAllChangedFilesFromString(this, status).ToList();
 
             if (!excludeAssumeUnchangedFiles || !excludeSkipWorktreeFiles)
             {
@@ -2560,7 +2560,7 @@ public IList<GitItemStatus> GetAllChangedFiles(bool excludeIgnoredFiles = true,
             return result;
         }
 
-        public IList<GitItemStatus> GetAllChangedFilesWithSubmodulesStatus(bool excludeIgnoredFiles = true,
+        public IReadOnlyList<GitItemStatus> GetAllChangedFilesWithSubmodulesStatus(bool excludeIgnoredFiles = true,
             bool excludeAssumeUnchangedFiles = true, bool excludeSkipWorktreeFiles = true,
             UntrackedFilesMode untrackedFiles = UntrackedFilesMode.Default)
         {
@@ -2569,7 +2569,7 @@ public IList<GitItemStatus> GetAllChangedFilesWithSubmodulesStatus(bool excludeI
             return status;
         }
 
-        private void GetCurrentSubmoduleStatus(IList<GitItemStatus> status)
+        private void GetCurrentSubmoduleStatus(IReadOnlyList<GitItemStatus> status)
         {
             foreach (var item in status)
             {
@@ -2591,7 +2591,7 @@ private void GetCurrentSubmoduleStatus(IList<GitItemStatus> status)
             }
         }
 
-        private void GetSubmoduleStatus(IList<GitItemStatus> status, string firstRevision, string secondRevision)
+        private void GetSubmoduleStatus(IReadOnlyList<GitItemStatus> status, string firstRevision, string secondRevision)
         {
             status.ForEach(item =>
             {
@@ -2614,7 +2614,7 @@ private void GetSubmoduleStatus(IList<GitItemStatus> status, string firstRevisio
             });
         }
 
-        public IList<GitItemStatus> GetStagedFiles()
+        public IReadOnlyList<GitItemStatus> GetStagedFiles()
         {
             string status = RunGitCmd(DiffCommandWithStandardArgs + "-M -C -z --cached --name-status", SystemEncoding);
 
@@ -2623,31 +2623,31 @@ public IList<GitItemStatus> GetStagedFiles()
                 // This command is a little more expensive because it will return both staged and unstaged files
                 string command = GitCommandHelpers.GetAllChangedFilesCmd(true, UntrackedFilesMode.No);
                 status = RunGitCmd(command, SystemEncoding);
-                IList<GitItemStatus> stagedFiles = GitCommandHelpers.GetAllChangedFilesFromString(this, status, false);
+                IReadOnlyList<GitItemStatus> stagedFiles = GitCommandHelpers.GetAllChangedFilesFromString(this, status, false);
                 return stagedFiles.Where(f => f.IsStaged).ToList();
             }
 
             return GitCommandHelpers.GetAllChangedFilesFromString(this, status, true);
         }
 
-        public IList<GitItemStatus> GetStagedFilesWithSubmodulesStatus()
+        public IReadOnlyList<GitItemStatus> GetStagedFilesWithSubmodulesStatus()
         {
             var status = GetStagedFiles();
             GetCurrentSubmoduleStatus(status);
             return status;
         }
 
-        public IList<GitItemStatus> GetUnstagedFiles()
+        public IReadOnlyList<GitItemStatus> GetUnstagedFiles()
         {
             return GetAllChangedFiles().Where(x => !x.IsStaged).ToArray();
         }
 
-        public IList<GitItemStatus> GetUnstagedFilesWithSubmodulesStatus()
+        public IReadOnlyList<GitItemStatus> GetUnstagedFilesWithSubmodulesStatus()
         {
             return GetAllChangedFilesWithSubmodulesStatus().Where(x => !x.IsStaged).ToArray();
         }
 
-        public IList<GitItemStatus> GitStatus(UntrackedFilesMode untrackedFilesMode, IgnoreSubmodulesMode ignoreSubmodulesMode = 0)
+        public IReadOnlyList<GitItemStatus> GitStatus(UntrackedFilesMode untrackedFilesMode, IgnoreSubmodulesMode ignoreSubmodulesMode = 0)
         {
             string command = GitCommandHelpers.GetAllChangedFilesCmd(true, untrackedFilesMode, ignoreSubmodulesMode);
             string status = RunGitCmd(command);
@@ -2832,9 +2832,9 @@ public IEnumerable<IGitRef> GetRemoteBranches()
             return GetRefs().Where(r => r.IsRemote);
         }
 
-        public RemoteActionResult<IList<IGitRef>> GetRemoteServerRefs(string remote, bool tags, bool branches)
+        public RemoteActionResult<IReadOnlyList<IGitRef>> GetRemoteServerRefs(string remote, bool tags, bool branches)
         {
-            var result = new RemoteActionResult<IList<IGitRef>>
+            var result = new RemoteActionResult<IReadOnlyList<IGitRef>>
             {
                 AuthenticationFail = false,
                 HostKeyFail = false,
@@ -2889,14 +2889,14 @@ private CmdResult GetTreeFromRemoteRefs(string remote, bool tags, bool branches)
             return GetTreeFromRemoteRefsEx(remote, tags, branches);
         }
 
-        public IList<IGitRef> GetRefs(bool tags = true, bool branches = true)
+        public IReadOnlyList<IGitRef> GetRefs(bool tags = true, bool branches = true)
         {
             var tree = GetTree(tags, branches);
             return GetTreeRefs(tree);
         }
 
         /// <param name="option">Ordery by date is slower.</param>
-        public IList<IGitRef> GetTagRefs(GetTagRefsSortOrder option)
+        public IReadOnlyList<IGitRef> GetTagRefs(GetTagRefsSortOrder option)
         {
             var list = GetRefs(true, false);
 
@@ -2984,7 +2984,7 @@ private string GetTree(bool tags, bool branches)
             return "";
         }
 
-        public IList<IGitRef> GetTreeRefs(string tree)
+        public IReadOnlyList<IGitRef> GetTreeRefs(string tree)
         {
             var itemsStrings = tree.Split('\n');
 
@@ -3131,7 +3131,7 @@ public string GetTagMessage(string tag)
         /// Returns list of filenames which would be ignored
         /// </summary>
         /// <param name="ignorePatterns">Patterns to ignore (.gitignore syntax)</param>
-        public IList<string> GetIgnoredFiles(IEnumerable<string> ignorePatterns)
+        public IReadOnlyList<string> GetIgnoredFiles(IEnumerable<string> ignorePatterns)
         {
             var notEmptyPatterns = ignorePatterns
                 .Where(pattern => !pattern.IsNullOrWhiteSpace())
@@ -3157,7 +3157,7 @@ public IList<string> GetIgnoredFiles(IEnumerable<string> ignorePatterns)
             }
         }
 
-        public string[] GetFullTree(string id)
+        public IReadOnlyList<string> GetFullTree(string id)
         {
             string tree = RunCacheableCmd(AppSettings.GitCommand, string.Format("ls-tree -z -r --name-only {0}", id), SystemEncoding);
             return tree.Split('\0', '\n');
@@ -3560,7 +3560,7 @@ public static string UnquoteFileName(string fileName)
             }
 
             char[] chars = fileName.ToCharArray();
-            IList<byte> blist = new List<byte>();
+            var blist = new List<byte>();
             int i = 0;
             StringBuilder sb = new StringBuilder();
             while (i < chars.Length)
@@ -3785,7 +3785,7 @@ public string GetLocalTrackingBranchName(string remoteName, string branch)
             return branchName;
         }
 
-        public IList<GitItemStatus> GetCombinedDiffFileList(string shaOfMergeCommit)
+        public IReadOnlyList<GitItemStatus> GetCombinedDiffFileList(string shaOfMergeCommit)
         {
             var fileList = RunGitCmd("diff-tree --name-only -z --cc --no-commit-id " + shaOfMergeCommit);
 
diff --git a/GitCommands/Git/GitVersion.cs b/GitCommands/Git/GitVersion.cs
index c910019d14f..84a127cc82e 100644
--- a/GitCommands/Git/GitVersion.cs
+++ b/GitCommands/Git/GitVersion.cs
@@ -30,7 +30,7 @@ public GitVersion(string version)
         {
             Full = Fix(version);
 
-            IList<int> numbers = GetNumbers(Full);
+            var numbers = GetNumbers(Full);
             _a = Get(numbers, 0);
             _b = Get(numbers, 1);
             _c = Get(numbers, 2);
@@ -107,12 +107,12 @@ private static string Fix(string version)
             return version.Trim();
         }
 
-        private static int Get(IList<int> values, int index)
+        private static int Get(IReadOnlyList<int> values, int index)
         {
             return index < values.Count ? values[index] : 0;
         }
 
-        private static IList<int> GetNumbers(string version)
+        private static IReadOnlyList<int> GetNumbers(string version)
         {
             IEnumerable<int> numbers = ParseNumbers(version);
             return new List<int>(numbers);
diff --git a/GitCommands/Remote/GitRemote.cs b/GitCommands/Remote/GitRemote.cs
index 703ab03f49c..fb8ec91f2a6 100644
--- a/GitCommands/Remote/GitRemote.cs
+++ b/GitCommands/Remote/GitRemote.cs
@@ -19,7 +19,7 @@ public class GitRemote
         /// <summary>
         /// Gets or sets value stored in .git/config via <see cref="SettingKeyString.RemotePush"/> key.
         /// </summary>
-        public IList<string> Push { get; set; }
+        public IReadOnlyList<string> Push { get; set; }
 
         /// <summary>
         /// Gets or sets value stored in .git/config via <see cref="SettingKeyString.RemotePushUrl"/> key.
diff --git a/GitCommands/RevisionGraph.cs b/GitCommands/RevisionGraph.cs
index 6baf873f483..cb4cd4f73ef 100644
--- a/GitCommands/RevisionGraph.cs
+++ b/GitCommands/RevisionGraph.cs
@@ -273,7 +273,7 @@ private void ProccessGitLogExecuted()
             Exited?.Invoke(this, EventArgs.Empty);
         }
 
-        private IList<IGitRef> GetRefs()
+        private IReadOnlyList<IGitRef> GetRefs()
         {
             var result = _module.GetRefs(true);
             bool validWorkingDir = _module.IsValidGitWorkingDir();
diff --git a/GitCommands/Settings/ConfigFileSettings.cs b/GitCommands/Settings/ConfigFileSettings.cs
index a0ed69c18d5..d06a96f3c0f 100644
--- a/GitCommands/Settings/ConfigFileSettings.cs
+++ b/GitCommands/Settings/ConfigFileSettings.cs
@@ -76,7 +76,7 @@ public string GetValue(string setting)
             return GetString(setting, string.Empty);
         }
 
-        public IList<string> GetValues(string setting)
+        public IReadOnlyList<string> GetValues(string setting)
         {
             return SettingsCache.GetValues(setting);
         }
@@ -97,7 +97,7 @@ public void SetPathValue(string setting, string value)
             SetValue(setting, ConfigSection.FixPath(value));
         }
 
-        public IList<IConfigSection> GetConfigSections()
+        public IReadOnlyList<IConfigSection> GetConfigSections()
         {
             return SettingsCache.GetConfigSections();
         }
diff --git a/GitCommands/Settings/ConfigFileSettingsCache.cs b/GitCommands/Settings/ConfigFileSettingsCache.cs
index 153f6ed39de..9daf260b1ee 100644
--- a/GitCommands/Settings/ConfigFileSettingsCache.cs
+++ b/GitCommands/Settings/ConfigFileSettingsCache.cs
@@ -83,7 +83,7 @@ public void AddConfigSection(IConfigSection configSection)
             });
         }
 
-        public IList<string> GetValues(string key)
+        public IReadOnlyList<string> GetValues(string key)
         {
             return LockedAction(() =>
             {
@@ -92,7 +92,7 @@ public IList<string> GetValues(string key)
             });
         }
 
-        public IList<IConfigSection> GetConfigSections()
+        public IReadOnlyList<IConfigSection> GetConfigSections()
         {
             return LockedAction(() =>
             {
diff --git a/GitCommands/Statistics/ImpactLoader.cs b/GitCommands/Statistics/ImpactLoader.cs
index d7a164b2fb0..8beff4f917f 100644
--- a/GitCommands/Statistics/ImpactLoader.cs
+++ b/GitCommands/Statistics/ImpactLoader.cs
@@ -128,7 +128,7 @@ private Task[] GetTasks(CancellationToken token)
 
             if (ShowSubmodules)
             {
-                IList<string> submodules = _module.GetSubmodulesLocalPaths();
+                var submodules = _module.GetSubmodulesLocalPaths();
                 foreach (var submoduleName in submodules)
                 {
                     IGitModule submodule = _module.GetSubmodule(submoduleName);
diff --git a/GitUI/CommandsDialogs/BrowseDialog/FormCommitCount.cs b/GitUI/CommandsDialogs/BrowseDialog/FormCommitCount.cs
index c7172c8c5ca..56d5ecdfe59 100644
--- a/GitUI/CommandsDialogs/BrowseDialog/FormCommitCount.cs
+++ b/GitUI/CommandsDialogs/BrowseDialog/FormCommitCount.cs
@@ -35,7 +35,8 @@ private void FetchData()
             var items = CommitCounter.GroupAllCommitsByContributor(Module).Item1;
             if (cbIncludeSubmodules.Checked)
             {
-                IList<string> submodules = Module.GetSubmodulesLocalPaths();
+                var submodules = Module.GetSubmodulesLocalPaths();
+
                 foreach (var submoduleName in submodules)
                 {
                     GitModule submodule = Module.GetSubmodule(submoduleName);
diff --git a/GitUI/CommandsDialogs/FormAddToGitIgnore.cs b/GitUI/CommandsDialogs/FormAddToGitIgnore.cs
index 5d6964dbd1b..fb7f1ef9139 100644
--- a/GitUI/CommandsDialogs/FormAddToGitIgnore.cs
+++ b/GitUI/CommandsDialogs/FormAddToGitIgnore.cs
@@ -96,7 +96,7 @@ private void AddToIgnoreClick(object sender, EventArgs e)
             Close();
         }
 
-        private void UpdatePreviewPanel(IList<string> ignoredFiles)
+        private void UpdatePreviewPanel(IReadOnlyList<string> ignoredFiles)
         {
             _NO_TRANSLATE_Preview.DataSource = ignoredFiles;
             _NO_TRANSLATE_filesWillBeIgnored.Text = string.Format(_matchingFilesString.Text, _NO_TRANSLATE_Preview.Items.Count);
diff --git a/GitUI/CommandsDialogs/FormBrowse.cs b/GitUI/CommandsDialogs/FormBrowse.cs
index b43df62342e..f253db9534d 100644
--- a/GitUI/CommandsDialogs/FormBrowse.cs
+++ b/GitUI/CommandsDialogs/FormBrowse.cs
@@ -1942,8 +1942,7 @@ private void AddBranchesMenuItems()
 
         private IEnumerable<string> GetBranchNames()
         {
-            IList<IGitRef> branches = Module.GetRefs(false);
-            IEnumerable<string> branchNames = branches.Select(b => b.Name);
+            IEnumerable<string> branchNames = Module.GetRefs(false).Select(b => b.Name);
             if (AppSettings.BranchOrderingCriteria == BranchOrdering.Alphabetically)
             {
                 branchNames = branchNames.OrderBy(b => b);
diff --git a/GitUI/CommandsDialogs/FormClone.cs b/GitUI/CommandsDialogs/FormClone.cs
index 9dd26c9720f..46c623b889d 100644
--- a/GitUI/CommandsDialogs/FormClone.cs
+++ b/GitUI/CommandsDialogs/FormClone.cs
@@ -407,7 +407,7 @@ private void ToSelectedIndexChanged(object sender, EventArgs e)
 
         private readonly AsyncLoader _branchListLoader = new AsyncLoader();
 
-        private void UpdateBranches(RemoteActionResult<IList<IGitRef>> branchList)
+        private void UpdateBranches(RemoteActionResult<IReadOnlyList<IGitRef>> branchList)
         {
             Cursor = Cursors.Default;
 
diff --git a/GitUI/CommandsDialogs/FormCommit.cs b/GitUI/CommandsDialogs/FormCommit.cs
index 76a8cbb523c..e8a8392edbd 100644
--- a/GitUI/CommandsDialogs/FormCommit.cs
+++ b/GitUI/CommandsDialogs/FormCommit.cs
@@ -509,9 +509,9 @@ protected override bool ExecuteCommand(int cmd)
 
         #endregion
 
-        private void ComputeUnstagedFiles(Action<IList<GitItemStatus>> onComputed, bool doAsync)
+        private void ComputeUnstagedFiles(Action<IReadOnlyList<GitItemStatus>> onComputed, bool doAsync)
         {
-            IList<GitItemStatus> GetAllChangedFilesWithSubmodulesStatus()
+            IReadOnlyList<GitItemStatus> GetAllChangedFilesWithSubmodulesStatus()
             {
                 return Module.GetAllChangedFilesWithSubmodulesStatus(
                     !showIgnoredFilesToolStripMenuItem.Checked,
@@ -778,7 +778,7 @@ private void InitializedStaged()
         ///   This method is passed in to the SetTextCallBack delegate
         ///   to set the Text property of textBox1.
         /// </summary>
-        private void LoadUnstagedOutput(IList<GitItemStatus> allChangedFiles)
+        private void LoadUnstagedOutput(IReadOnlyList<GitItemStatus> allChangedFiles)
         {
             var lastSelection = new List<GitItemStatus>();
             if (_currentFilesList != null)
diff --git a/GitUI/CommandsDialogs/FormPull.cs b/GitUI/CommandsDialogs/FormPull.cs
index 855e58289a8..eb116ea7dc6 100644
--- a/GitUI/CommandsDialogs/FormPull.cs
+++ b/GitUI/CommandsDialogs/FormPull.cs
@@ -96,7 +96,7 @@ public partial class FormPull : GitModuleForm
         #endregion
 
         public bool ErrorOccurred { get; private set; }
-        private IList<IGitRef> _heads;
+        private List<IGitRef> _heads;
         private string _branch;
         private bool _bInternalUpdate;
         private const string AllRemotes = "[ All ]";
@@ -235,7 +235,7 @@ private void BranchesDropDown(object sender, EventArgs e)
             {
                 if (PullFromUrl.Checked)
                 {
-                    _heads = Module.GetRefs(false, true);
+                    _heads = Module.GetRefs(false, true).ToList();
                 }
                 else
                 {
diff --git a/GitUI/CommandsDialogs/FormPush.cs b/GitUI/CommandsDialogs/FormPush.cs
index 8837877ef4c..255f4058dcc 100644
--- a/GitUI/CommandsDialogs/FormPush.cs
+++ b/GitUI/CommandsDialogs/FormPush.cs
@@ -27,7 +27,7 @@ public partial class FormPush : GitModuleForm
         private string _selectedBranch;
         private GitRemote _selectedRemote;
         private string _selectedRemoteBranchName;
-        private IList<IGitRef> _gitRefs;
+        private IReadOnlyList<IGitRef> _gitRefs;
         private readonly IGitRemoteManager _remoteManager;
 
         public bool ErrorOccurred { get; private set; }
@@ -906,7 +906,7 @@ private void LoadMultiBranchViewData(string remote)
             Cursor = Cursors.AppStarting;
             try
             {
-                IList<IGitRef> remoteHeads;
+                IReadOnlyList<IGitRef> remoteHeads;
                 if (Module.EffectiveSettings.Detailed.GetRemoteBranchesDirectlyFromRemote.ValueOrDefault)
                 {
                     EnsurePageant(remote);
@@ -959,7 +959,7 @@ private static string TakeCommandOutput(string processOutput)
             return cmdOutput;
         }
 
-        private void ProcessHeads(string remote, IList<IGitRef> remoteHeads)
+        private void ProcessHeads(string remote, IReadOnlyList<IGitRef> remoteHeads)
         {
             IList<IGitRef> localHeads = GetLocalBranches().ToList();
             var remoteBranches = remoteHeads.ToHashSet(h => h.LocalName);
diff --git a/GitUI/CommandsDialogs/FormStash.cs b/GitUI/CommandsDialogs/FormStash.cs
index 7ef7d13170f..23231dfa9c4 100644
--- a/GitUI/CommandsDialogs/FormStash.cs
+++ b/GitUI/CommandsDialogs/FormStash.cs
@@ -63,7 +63,7 @@ private void FormStashLoad(object sender, EventArgs e)
 
         private void Initialize()
         {
-            IList<GitStash> stashedItems = Module.GetStashes();
+            var stashedItems = Module.GetStashes().ToList();
 
             _currentWorkingDirStashItem = new GitStash("currentWorkingDirStashItem")
             {
@@ -120,7 +120,7 @@ private void InitializeSoft()
             }
         }
 
-        private void LoadGitItemStatuses(IList<GitItemStatus> gitItemStatuses)
+        private void LoadGitItemStatuses(IReadOnlyList<GitItemStatus> gitItemStatuses)
         {
             Stashed.SetDiffs(items: gitItemStatuses);
             Loading.Visible = false;
diff --git a/GitUI/CommandsDialogs/SubmodulesDialog/FormAddSubmodule.cs b/GitUI/CommandsDialogs/SubmodulesDialog/FormAddSubmodule.cs
index a89a7cadc82..9cf29339069 100644
--- a/GitUI/CommandsDialogs/SubmodulesDialog/FormAddSubmodule.cs
+++ b/GitUI/CommandsDialogs/SubmodulesDialog/FormAddSubmodule.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Windows.Forms;
 using GitCommands;
 using GitCommands.Repository;
@@ -63,10 +64,10 @@ private void BranchDropDown(object sender, EventArgs e)
         {
             GitModule module = new GitModule(Directory.Text);
             Branch.DisplayMember = "Name";
-            IList<IGitRef> heads;
+            List<IGitRef> heads;
             if (module.IsValidGitWorkingDir())
             {
-                heads = module.GetRefs(false);
+                heads = module.GetRefs(false).ToList();
             }
             else
             {
diff --git a/GitUI/CommandsDialogs/WorktreeDialog/FormCreateWorktree.cs b/GitUI/CommandsDialogs/WorktreeDialog/FormCreateWorktree.cs
index 495a970c096..112c8b5717e 100644
--- a/GitUI/CommandsDialogs/WorktreeDialog/FormCreateWorktree.cs
+++ b/GitUI/CommandsDialogs/WorktreeDialog/FormCreateWorktree.cs
@@ -68,7 +68,7 @@ private void LoadBranchesAsync()
             }, TaskScheduler.FromCurrentSynchronizationContext());
         }
 
-        public IList<IGitRef> ExistingBranches { get; set; }
+        public IReadOnlyList<IGitRef> ExistingBranches { get; set; }
 
         private void comboBoxBranches_KeyUp(object sender, KeyEventArgs e)
         {
diff --git a/GitUI/CommitInfo/CommitInfo.cs b/GitUI/CommitInfo/CommitInfo.cs
index 4bc592f68b5..724d6aab91e 100644
--- a/GitUI/CommitInfo/CommitInfo.cs
+++ b/GitUI/CommitInfo/CommitInfo.cs
@@ -223,7 +223,7 @@ private int GetRevisionHeaderHeight()
 
         private void LoadSortedRefs()
         {
-            _sortedRefs = Module.GetSortedRefs();
+            _sortedRefs = Module.GetSortedRefs().ToList();
             this.InvokeAsync(UpdateRevisionInfo);
         }
 
diff --git a/GitUI/HelperDialogs/FormSelectMultipleBranches.cs b/GitUI/HelperDialogs/FormSelectMultipleBranches.cs
index 0dcc9423817..8c3bd3834b2 100644
--- a/GitUI/HelperDialogs/FormSelectMultipleBranches.cs
+++ b/GitUI/HelperDialogs/FormSelectMultipleBranches.cs
@@ -15,7 +15,7 @@ private FormSelectMultipleBranches()
             Translate();
         }
 
-        public FormSelectMultipleBranches(IList<IGitRef> branchesToSelect)
+        public FormSelectMultipleBranches(IReadOnlyList<IGitRef> branchesToSelect)
         {
             InitializeComponent();
             Translate();
@@ -44,9 +44,9 @@ public void SelectBranch(string name)
             }
         }
 
-        public IList<IGitRef> GetSelectedBranches()
+        public IReadOnlyList<IGitRef> GetSelectedBranches()
         {
-            IList<IGitRef> branches = new List<IGitRef>();
+            var branches = new List<IGitRef>();
 
             foreach (IGitRef head in Branches.CheckedItems)
             {
diff --git a/GitUI/UserControls/BranchComboBox.cs b/GitUI/UserControls/BranchComboBox.cs
index 8d4b9d1c92b..ef5b64cbe08 100644
--- a/GitUI/UserControls/BranchComboBox.cs
+++ b/GitUI/UserControls/BranchComboBox.cs
@@ -21,8 +21,8 @@ public BranchComboBox()
             branches.DisplayMember = "Name";
         }
 
-        private IList<IGitRef> _branchesToSelect;
-        public IList<IGitRef> BranchesToSelect
+        private IReadOnlyList<IGitRef> _branchesToSelect;
+        public IReadOnlyList<IGitRef> BranchesToSelect
         {
             get
             {
@@ -76,7 +76,7 @@ public void SetSelectedText(string text)
 
         private void selectMultipleBranchesButton_Click(object sender, EventArgs e)
         {
-            using (FormSelectMultipleBranches formSelectMultipleBranches = new FormSelectMultipleBranches(_branchesToSelect))
+            using (var formSelectMultipleBranches = new FormSelectMultipleBranches(_branchesToSelect))
             {
                 foreach (var branch in GetSelectedBranches())
                 {
diff --git a/GitUI/UserControls/FileStatusList.cs b/GitUI/UserControls/FileStatusList.cs
index 64f0cd6b6ea..cc68f000c9f 100644
--- a/GitUI/UserControls/FileStatusList.cs
+++ b/GitUI/UserControls/FileStatusList.cs
@@ -19,8 +19,8 @@
 namespace GitUI
 {
     // Parents is used as the "first selected" (not always the parent) for GitItemStatus
-    using IGitItemsWithParents = IDictionary<GitRevision, IList<GitItemStatus>>;
-    using GitItemsWithParents = Dictionary<GitRevision, IList<GitItemStatus>>;
+    using IGitItemsWithParents = IDictionary<GitRevision, IReadOnlyList<GitItemStatus>>;
+    using GitItemsWithParents = Dictionary<GitRevision, IReadOnlyList<GitItemStatus>>;
 
     public delegate string DescribeRevisionDelegate(string sha1);
 
@@ -1117,7 +1117,7 @@ private int SelectFiles(Regex selctionFilter)
             }
         }
 
-        public void SetDiffs(GitRevision selectedRev = null, GitRevision parentRev = null, IList<GitItemStatus> items = null)
+        public void SetDiffs(GitRevision selectedRev = null, GitRevision parentRev = null, IReadOnlyList<GitItemStatus> items = null)
         {
             Revision = selectedRev;
 
diff --git a/GitUI/UserControls/PatchGrid.cs b/GitUI/UserControls/PatchGrid.cs
index 233e4d7cc71..72123c88af9 100644
--- a/GitUI/UserControls/PatchGrid.cs
+++ b/GitUI/UserControls/PatchGrid.cs
@@ -33,7 +33,7 @@ protected override void OnRuntimeLoad(EventArgs e)
 
         public void Initialize()
         {
-            IList<PatchFile> patchFiles;
+            IReadOnlyList<PatchFile> patchFiles;
 
             if (Module.InTheMiddleOfInteractiveRebase())
             {
diff --git a/Plugins/GitUIPluginInterfaces/IConfigFileSettings.cs b/Plugins/GitUIPluginInterfaces/IConfigFileSettings.cs
index 2ab5ed3a361..17edc4088df 100644
--- a/Plugins/GitUIPluginInterfaces/IConfigFileSettings.cs
+++ b/Plugins/GitUIPluginInterfaces/IConfigFileSettings.cs
@@ -13,7 +13,7 @@ public interface IConfigFileSettings : ISettingsValueGetter
         /// <summary>
         /// Retrieves configuration sections the .git/config file.
         /// </summary>
-        IList<IConfigSection> GetConfigSections();
+        IReadOnlyList<IConfigSection> GetConfigSections();
 
         /// <summary>
         /// Removes the specific configuration section from the .git/config file.
diff --git a/Plugins/GitUIPluginInterfaces/IConfigSection.cs b/Plugins/GitUIPluginInterfaces/IConfigSection.cs
index f60905968b2..d9e29ec69db 100644
--- a/Plugins/GitUIPluginInterfaces/IConfigSection.cs
+++ b/Plugins/GitUIPluginInterfaces/IConfigSection.cs
@@ -7,11 +7,11 @@ public interface IConfigSection
         string SectionName { get; set; }
         string SubSection { get; set; }
 
-        IDictionary<string, IList<string>> AsDictionary();
+        IDictionary<string, IReadOnlyList<string>> AsDictionary();
         void AddValue(string key, string value);
         bool Equals(IConfigSection other);
         string GetValue(string key, string defaultValue = "");
-        IList<string> GetValues(string key);
+        IReadOnlyList<string> GetValues(string key);
         bool HasValue(string key);
         void SetValue(string key, string value);
     }
diff --git a/Plugins/GitUIPluginInterfaces/IGitModule.cs b/Plugins/GitUIPluginInterfaces/IGitModule.cs
index 8100bc526ba..a342d4e14de 100644
--- a/Plugins/GitUIPluginInterfaces/IGitModule.cs
+++ b/Plugins/GitUIPluginInterfaces/IGitModule.cs
@@ -11,7 +11,7 @@ public interface IGitModule
         IConfigFileSettings LocalConfigFile { get; }
 
         string AddRemote(string remoteName, string path);
-        IList<IGitRef> GetRefs(bool tags = true, bool branches = true);
+        IReadOnlyList<IGitRef> GetRefs(bool tags = true, bool branches = true);
         IEnumerable<string> GetSettings(string setting);
         IEnumerable<IGitItem> GetTree(string id, bool full);
 
@@ -106,7 +106,7 @@ public interface IGitModule
 
         IEnumerable<IGitSubmoduleInfo> GetSubmodulesInfo();
 
-        IList<string> GetSubmodulesLocalPaths(bool recursive = true);
+        IReadOnlyList<string> GetSubmodulesLocalPaths(bool recursive = true);
 
         IGitModule GetSubmodule(string submoduleName);
 
diff --git a/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs b/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs
index 1548015171c..48109061009 100644
--- a/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs
+++ b/UnitTests/GitCommandsTests/Git/GitCommandHelpersTest.cs
@@ -115,7 +115,7 @@ public void TestGetAllChangedFilesFromString()
             {
                 // git diff -M -C -z --cached --name-status
                 string statusString = "\r\nwarning: LF will be replaced by CRLF in CustomDictionary.xml.\r\nThe file will have its original line endings in your working directory.\r\nwarning: LF will be replaced by CRLF in FxCop.targets.\r\nThe file will have its original line endings in your working directory.\r\nM\0testfile.txt\0";
-                List<GitItemStatus> status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
+                var status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
                 Assert.IsTrue(status.Count == 1);
                 Assert.IsTrue(status[0].Name == "testfile.txt");
             }
@@ -123,7 +123,7 @@ public void TestGetAllChangedFilesFromString()
             {
                 // git diff -M -C -z --cached --name-status
                 string statusString = "\0\r\nwarning: LF will be replaced by CRLF in CustomDictionary.xml.\r\nThe file will have its original line endings in your working directory.\r\nwarning: LF will be replaced by CRLF in FxCop.targets.\r\nThe file will have its original line endings in your working directory.\r\nM\0testfile.txt\0";
-                List<GitItemStatus> status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
+                var status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
                 Assert.IsTrue(status.Count == 1);
                 Assert.IsTrue(status[0].Name == "testfile.txt");
             }
@@ -131,7 +131,7 @@ public void TestGetAllChangedFilesFromString()
             {
                 // git diff -M -C -z --cached --name-status
                 string statusString = "\0\nwarning: LF will be replaced by CRLF in CustomDictionary.xml.\nThe file will have its original line endings in your working directory.\nwarning: LF will be replaced by CRLF in FxCop.targets.\nThe file will have its original line endings in your working directory.\nM\0testfile.txt\0";
-                List<GitItemStatus> status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
+                var status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
                 Assert.IsTrue(status.Count == 1);
                 Assert.IsTrue(status[0].Name == "testfile.txt");
             }
@@ -139,7 +139,7 @@ public void TestGetAllChangedFilesFromString()
             {
                 // git diff -M -C -z --cached --name-status
                 string statusString = "M  testfile.txt\0\nwarning: LF will be replaced by CRLF in CustomDictionary.xml.\nThe file will have its original line endings in your working directory.\nwarning: LF will be replaced by CRLF in FxCop.targets.\nThe file will have its original line endings in your working directory.\n";
-                List<GitItemStatus> status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
+                var status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, true);
                 Assert.IsTrue(status.Count == 1);
                 Assert.IsTrue(status[0].Name == "testfile.txt");
             }
@@ -147,7 +147,7 @@ public void TestGetAllChangedFilesFromString()
             {
                 // git status --porcelain --untracked-files=no -z
                 string statusString = "M  adfs.h\0M  dir.c\0\r\nwarning: LF will be replaced by CRLF in adfs.h.\nThe file will have its original line endings in your working directory.\nwarning: LF will be replaced by CRLF in dir.c.\nThe file will have its original line endings in your working directory.";
-                List<GitItemStatus> status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, false);
+                var status = GitCommandHelpers.GetAllChangedFilesFromString(module, statusString, false);
                 Assert.IsTrue(status.Count == 2);
                 Assert.IsTrue(status[0].Name == "adfs.h");
                 Assert.IsTrue(status[1].Name == "dir.c");