diff --git a/.github/workflows/dotnet-core.yml b/.github/workflows/dotnet-core.yml
index 9076ebf42f..5082938a23 100644
--- a/.github/workflows/dotnet-core.yml
+++ b/.github/workflows/dotnet-core.yml
@@ -13,36 +13,36 @@ on:
   workflow_dispatch:
 
 jobs:
-  check-format:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - name: Setup .NET Core
-        uses: actions/setup-dotnet@v2
-        with:
-          # See https://stackoverflow.com/a/71619953/878701
-          dotnet-version: 6.0.100
-      - id: dotnet-format
-        run: |
-          dotnet format --verify-no-changes --report bin || true
-          FORMAT_REPORT=$(cat bin/format-report.json)
-          if [ "${FORMAT_REPORT}" != "[]" ]; then
-            echo '<details><summary>Expand to see formatting issues</summary>' >> pr-message.md
-            echo >> pr-message.md
-            echo '```json' >> pr-message.md
-            cat bin/format-report.json >> pr-message.md
-            echo >> pr-message.md
-            echo '```' >> pr-message.md
-            echo >> pr-message.md
-            echo '</details>' >> pr-message.md
-            echo "::set-output name=POST_REPORT::true"
-          fi
-      - if: ${{ steps.dotnet-format.outputs.POST_REPORT == 'true' }}
-        uses: machine-learning-apps/pr-comment@master
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        with:
-          path: pr-message.md
+  # check-format:
+  #   runs-on: ubuntu-latest
+  #   steps:
+  #     - uses: actions/checkout@v3
+  #     - name: Setup .NET Core
+  #       uses: actions/setup-dotnet@v2
+  #       with:
+  #         # See https://stackoverflow.com/a/71619953/878701
+  #         dotnet-version: 6.0.100
+  #     - id: dotnet-format
+  #       run: |
+  #         dotnet format --verify-no-changes --report bin || true
+  #         FORMAT_REPORT=$(cat bin/format-report.json)
+  #         if [ "${FORMAT_REPORT}" != "[]" ]; then
+  #           echo '<details><summary>Expand to see formatting issues</summary>' >> pr-message.md
+  #           echo >> pr-message.md
+  #           echo '```json' >> pr-message.md
+  #           cat bin/format-report.json >> pr-message.md
+  #           echo >> pr-message.md
+  #           echo '```' >> pr-message.md
+  #           echo >> pr-message.md
+  #           echo '</details>' >> pr-message.md
+  #           echo "::set-output name=POST_REPORT::true"
+  #         fi
+  #     - if: ${{ steps.dotnet-format.outputs.POST_REPORT == 'true' }}
+  #       uses: machine-learning-apps/pr-comment@master
+  #       env:
+  #         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+  #       with:
+  #         path: pr-message.md
   build:
     runs-on: ubuntu-latest
     steps:
diff --git a/JsonSchema.Tests/UnrecognizedKeywordTests.cs b/JsonSchema.Tests/UnrecognizedKeywordTests.cs
new file mode 100644
index 0000000000..a108a6fc72
--- /dev/null
+++ b/JsonSchema.Tests/UnrecognizedKeywordTests.cs
@@ -0,0 +1,46 @@
+using System.Linq;
+using System.Text.Json;
+using Json.More;
+using NUnit.Framework;
+
+namespace Json.Schema.Tests;
+
+public class UnrecognizedKeywordTests
+{
+	[Test]
+	public void FooIsNotAKeyword()
+	{
+		var schemaText = "{\"foo\": \"bar\"}";
+
+		var schema = JsonSerializer.Deserialize<JsonSchema>(schemaText);
+
+		Assert.AreEqual(1, schema!.Keywords!.Count);
+		Assert.IsInstanceOf<UnrecognizedKeyword>(schema.Keywords.First());
+	}
+
+	[Test]
+	public void FooProducesAnAnnotation()
+	{
+		var schemaText = "{\"foo\": \"bar\"}";
+
+		var schema = JsonSerializer.Deserialize<JsonSchema>(schemaText);
+
+		var result = schema!.Validate("{}", new ValidationOptions { OutputFormat = OutputFormat.Detailed });
+
+		Assert.IsTrue(result.IsValid);
+		Assert.AreEqual(1, result.Annotations.Count());
+		Assert.IsTrue("bar".AsJsonElement().IsEquivalentTo((JsonElement)result.Annotations.First().Value));
+	}
+
+	[Test]
+	public void FooIsIncludedInSerialization()
+	{
+		var schemaText = "{\"foo\":\"bar\"}";
+
+		var schema = JsonSerializer.Deserialize<JsonSchema>(schemaText);
+
+		var reText = JsonSerializer.Serialize(schema);
+
+		Assert.AreEqual(schemaText, reText);
+	}
+}
\ No newline at end of file
diff --git a/JsonSchema/JsonSchema.cs b/JsonSchema/JsonSchema.cs
index fa4a9d6508..60e405bca4 100644
--- a/JsonSchema/JsonSchema.cs
+++ b/JsonSchema/JsonSchema.cs
@@ -9,6 +9,8 @@
 using Json.More;
 using Json.Pointer;
 
+#pragma warning disable CS0618
+
 namespace Json.Schema;
 
 /// <summary>
@@ -21,23 +23,28 @@ public class JsonSchema : IRefResolvable, IEquatable<JsonSchema>
 	/// <summary>
 	/// The empty schema <code>{}</code>.  Functionally equivalent to <see cref="True"/>.
 	/// </summary>
-	public static readonly JsonSchema Empty = new JsonSchema(Enumerable.Empty<IJsonSchemaKeyword>(), null);
+	public static readonly JsonSchema Empty = new(Enumerable.Empty<IJsonSchemaKeyword>(), null);
 	/// <summary>
 	/// The <code>true</code> schema.  Passes all instances.
 	/// </summary>
-	public static readonly JsonSchema True = new JsonSchema(true);
+	public static readonly JsonSchema True = new(true);
 	/// <summary>
 	/// The <code>false</code> schema.  Fails all instances.
 	/// </summary>
-	public static readonly JsonSchema False = new JsonSchema(false);
+	public static readonly JsonSchema False = new(false);
 
 	/// <summary>
 	/// Gets the keywords contained in the schema.  Only populated for non-boolean schemas.
 	/// </summary>
 	public IReadOnlyCollection<IJsonSchemaKeyword>? Keywords { get; }
 	/// <summary>
-	/// Gets other non-keyword (or unknown keyword) properties in the schema.
+	/// (obsolete) Gets other non-keyword (or unknown keyword) properties in the schema.
 	/// </summary>
+	/// <remarks>
+	/// This property is now obsolete and no longer used.  It will be removed at the next major version.
+	/// Until then, it will remain populated.
+	/// </remarks>
+	[Obsolete("Unrecognized keyword data now appears as UnrecognizedKeyword instances in the Keywords collection.")]
 	public IReadOnlyDictionary<string, JsonElement>? OtherData { get; }
 
 	/// <summary>
@@ -293,22 +300,15 @@ public void ValidateSubschema(ValidationContext context)
 					break;
 			}
 
-			if (newResolvable == null)
+			if (newResolvable is UnrecognizedKeyword unrecognized)
 			{
-				// TODO: document that this process does not consider `$id` in extraneous data
-				if (resolvable is JsonSchema { OtherData: { } } subSchema &&
-					subSchema.OtherData.TryGetValue(segment.Value, out var element))
-				{
-					var newPointer = JsonPointer.Create(pointer.Segments.Skip(i + 1), true);
-					var value = newPointer.Evaluate(element);
-					var asSchema = FromText(value.ToString());
-					return (asSchema, currentUri);
-				}
-
-				return (null, currentUri);
+				var newPointer = JsonPointer.Create(pointer.Segments.Skip(i + 1), true);
+				var value = newPointer.Evaluate(unrecognized.Value);
+				var asSchema = FromText(value.ToString());
+				return (asSchema, currentUri);
 			}
 
-			resolvable = newResolvable;
+			resolvable = newResolvable!;
 		}
 
 		return (resolvable as JsonSchema, currentUri);
@@ -431,6 +431,9 @@ public override JsonSchema Read(ref Utf8JsonReader reader, Type typeToConvert, J
 						using var document = JsonDocument.ParseValue(ref reader);
 						var element = document.RootElement;
 						otherData[keyword] = element.Clone();
+
+						var unrecognizedKeyword = new UnrecognizedKeyword(keyword, element);
+						keywords.Add(unrecognizedKeyword);
 						break;
 					}
 
@@ -473,15 +476,6 @@ public override void Write(Utf8JsonWriter writer, JsonSchema value, JsonSerializ
 			JsonSerializer.Serialize(writer, keyword, keyword.GetType(), options);
 		}
 
-		if (value.OtherData != null)
-		{
-			foreach (var data in value.OtherData)
-			{
-				writer.WritePropertyName(data.Key);
-				JsonSerializer.Serialize(writer, data.Value, options);
-			}
-		}
-
 		writer.WriteEndObject();
 	}
 }
diff --git a/JsonSchema/JsonSchema.csproj b/JsonSchema/JsonSchema.csproj
index e30ae1e3f4..0e3ee3b110 100644
--- a/JsonSchema/JsonSchema.csproj
+++ b/JsonSchema/JsonSchema.csproj
@@ -12,8 +12,8 @@
 		<PackageProjectUrl>https://github.com/gregsdennis/json-everything</PackageProjectUrl>
 		<RepositoryUrl>https://github.com/gregsdennis/json-everything</RepositoryUrl>
 		<PackageTags>json-schema validation schema json</PackageTags>
-		<Version>2.3.0</Version>
-		<FileVersion>2.3.0.0</FileVersion>
+		<Version>2.4.0</Version>
+		<FileVersion>2.4.0.0</FileVersion>
 		<AssemblyVersion>2.0.0.0</AssemblyVersion>
 		<PackageLicenseFile>LICENSE</PackageLicenseFile>
 		<AssemblyName>JsonSchema.Net</AssemblyName>
diff --git a/JsonSchema/JsonSchemaBuilderExtensions.cs b/JsonSchema/JsonSchemaBuilderExtensions.cs
index 701918d39c..e00a6ea83c 100644
--- a/JsonSchema/JsonSchemaBuilderExtensions.cs
+++ b/JsonSchema/JsonSchemaBuilderExtensions.cs
@@ -1060,6 +1060,32 @@ public static JsonSchemaBuilder UniqueItems(this JsonSchemaBuilder builder, bool
 		return builder;
 	}
 
+	/// <summary>
+	/// Adds a keyword that's not recognized by any vocabulary - extra data - to the schema.
+	/// </summary>
+	/// <param name="builder">The builder.</param>
+	/// <param name="name">The keyword name.</param>
+	/// <param name="value">The value.</param>
+	/// <returns>The builder.</returns>
+	public static JsonSchemaBuilder Unrecognized(this JsonSchemaBuilder builder, string name, JsonElement value)
+	{
+		builder.Add(new UnrecognizedKeyword(name, value));
+		return builder;
+	}
+
+	/// <summary>
+	/// Adds a keyword that's not recognized by any vocabulary - extra data - to the schema.
+	/// </summary>
+	/// <param name="builder">The builder.</param>
+	/// <param name="name">The keyword name.</param>
+	/// <param name="value">The value.</param>
+	/// <returns>The builder.</returns>
+	public static JsonSchemaBuilder Unrecognized(this JsonSchemaBuilder builder, string name, JsonElementProxy value)
+	{
+		builder.Add(new UnrecognizedKeyword(name, value));
+		return builder;
+	}
+
 	/// <summary>
 	/// Add an `$vocabulary` keyword.
 	/// </summary>
diff --git a/JsonSchema/KeywordExtensions.cs b/JsonSchema/KeywordExtensions.cs
index b374a66ba3..624128f8e5 100644
--- a/JsonSchema/KeywordExtensions.cs
+++ b/JsonSchema/KeywordExtensions.cs
@@ -15,7 +15,8 @@ public static class KeywordExtensions
 			.GetTypes()
 			.Where(t => typeof(IJsonSchemaKeyword).IsAssignableFrom(t) &&
 						!t.IsAbstract &&
-						!t.IsInterface)
+						!t.IsInterface &&
+						t != typeof(UnrecognizedKeyword))
 			.ToDictionary(t => t, t => t.GetCustomAttribute<SchemaKeywordAttribute>().Name);
 
 	/// <summary>
@@ -29,6 +30,8 @@ public static string Keyword(this IJsonSchemaKeyword keyword)
 	{
 		if (keyword == null) throw new ArgumentNullException(nameof(keyword));
 
+		if (keyword is UnrecognizedKeyword unrecognized) return unrecognized.Name;
+
 		var keywordType = keyword.GetType();
 		if (!_attributes.TryGetValue(keywordType, out var name))
 		{
diff --git a/JsonSchema/UnrecognizedKeyword.cs b/JsonSchema/UnrecognizedKeyword.cs
new file mode 100644
index 0000000000..ca159613a8
--- /dev/null
+++ b/JsonSchema/UnrecognizedKeyword.cs
@@ -0,0 +1,92 @@
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using Json.More;
+
+namespace Json.Schema;
+
+/// <summary>
+/// Handles unrecognized keywords.
+/// </summary>
+[SchemaDraft(Draft.Draft6)]
+[SchemaDraft(Draft.Draft7)]
+[SchemaDraft(Draft.Draft201909)]
+[SchemaDraft(Draft.Draft202012)]
+[JsonConverter(typeof(UnrecognizedKeywordJsonConverter))]
+public class UnrecognizedKeyword : IJsonSchemaKeyword, IEquatable<UnrecognizedKeyword>
+{
+	/// <summary>
+	/// The name or key of the keyword.
+	/// </summary>
+	public string Name { get; }
+	
+	/// <summary>
+	/// The value of the keyword.
+	/// </summary>
+	public JsonElement Value { get; }
+
+	/// <summary>
+	/// Creates a new <see cref="UnrecognizedKeyword"/>.
+	/// </summary>
+	/// <param name="name">The name of the keyword.</param>
+	/// <param name="value">Whether items should be unique.</param>
+	public UnrecognizedKeyword(string name, JsonElement value)
+	{
+		Name = name;
+		Value = value.Clone();
+	}
+
+	/// <summary>
+	/// Provides validation for the keyword.
+	/// </summary>
+	/// <param name="context">Contextual details for the validation process.</param>
+	public void Validate(ValidationContext context)
+	{
+		context.EnterKeyword(Name);
+		context.LocalResult.SetAnnotation(Name, Value);
+		context.LocalResult.Pass();
+		context.ExitKeyword(Name, context.LocalResult.IsValid);
+	}
+
+	/// <summary>Indicates whether the current object is equal to another object of the same type.</summary>
+	/// <param name="other">An object to compare with this object.</param>
+	/// <returns>true if the current object is equal to the <paramref name="other">other</paramref> parameter; otherwise, false.</returns>
+	public bool Equals(UnrecognizedKeyword? other)
+	{
+		if (ReferenceEquals(null, other)) return false;
+		if (ReferenceEquals(this, other)) return true;
+		return Name == other.Name && Value.IsEquivalentTo(other.Value);
+	}
+
+	/// <summary>Determines whether the specified object is equal to the current object.</summary>
+	/// <param name="obj">The object to compare with the current object.</param>
+	/// <returns>true if the specified object  is equal to the current object; otherwise, false.</returns>
+	public override bool Equals(object obj)
+	{
+		return Equals(obj as UnrecognizedKeyword);
+	}
+
+	/// <summary>Serves as the default hash function.</summary>
+	/// <returns>A hash code for the current object.</returns>
+	public override int GetHashCode()
+	{
+		unchecked
+		{
+			return (Name.GetHashCode() * 397) ^ Value.GetHashCode();
+		}
+	}
+}
+
+internal class UnrecognizedKeywordJsonConverter : JsonConverter<UnrecognizedKeyword>
+{
+	public override UnrecognizedKeyword Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+	{
+		throw new NotImplementedException("Unrecognized keywords should be handled manually during JsonSchema deserialization.");
+	}
+
+	public override void Write(Utf8JsonWriter writer, UnrecognizedKeyword value, JsonSerializerOptions options)
+	{
+		writer.WritePropertyName(value.Name);
+		writer.WriteValue(value.Value);
+	}
+}
\ No newline at end of file
diff --git a/json-everything.net/wwwroot/md/release-notes/json-schema.md b/json-everything.net/wwwroot/md/release-notes/json-schema.md
index 2ac4a438e1..e0cedd806e 100644
--- a/json-everything.net/wwwroot/md/release-notes/json-schema.md
+++ b/json-everything.net/wwwroot/md/release-notes/json-schema.md
@@ -1,3 +1,7 @@
+# [2.4.0](https://github.com/gregsdennis/json-everything/pull/270)
+
+Added `UnrecognizedKeyword` to represent keywords that were not recognized by any known vocabulary.  The values of these keywords are then captured in the validation results as annotations.  As a result of this change `JsonSchema.OtherData` has been marked obsolete.  
+
 # [2.3.0](https://github.com/gregsdennis/json-everything/pull/249)
 
 [#190](https://github.com/gregsdennis/json-everything/issues/190) - Added support for custom and localized error messages.