diff --git a/Library/Homebrew/cleanup.rb b/Library/Homebrew/cleanup.rb
index 480a9c9ca1623..3003de496b077 100644
--- a/Library/Homebrew/cleanup.rb
+++ b/Library/Homebrew/cleanup.rb
@@ -84,7 +84,7 @@ def stale_formula?(scrub)
         return true
       end
 
-      return true if scrub && !formula.installed?
+      return true if scrub && !formula.latest_version_installed?
 
       return true if Utils::Bottles.file_outdated?(formula, self)
 
diff --git a/Library/Homebrew/cli/args.rb b/Library/Homebrew/cli/args.rb
index 202b5557db071..b8b35b36e4b82 100644
--- a/Library/Homebrew/cli/args.rb
+++ b/Library/Homebrew/cli/args.rb
@@ -84,11 +84,7 @@ def formulae
         require "formula"
 
         @formulae ||= (downcased_unique_named - casks).map do |name|
-          if name.include?("/") || File.exist?(name)
-            Formulary.factory(name, spec)
-          else
-            Formulary.find_with_priority(name, spec)
-          end
+          Formulary.factory(name, spec)
         end.uniq(&:name).freeze
       end
 
diff --git a/Library/Homebrew/cli/parser.rb b/Library/Homebrew/cli/parser.rb
index 53efc0058409f..5486f464b8bd5 100644
--- a/Library/Homebrew/cli/parser.rb
+++ b/Library/Homebrew/cli/parser.rb
@@ -359,11 +359,7 @@ def formulae
         named_args.map do |arg|
           next if arg.match?(HOMEBREW_CASK_TAP_CASK_REGEX)
 
-          if arg.include?("/") || arg.end_with?(".tar.gz") || File.exist?(arg)
-            Formulary.factory(arg, spec)
-          else
-            Formulary.find_with_priority(arg.downcase, spec)
-          end
+          Formulary.factory(arg, spec)
         end.compact.uniq(&:name)
       end
     end
diff --git a/Library/Homebrew/cmd/--env.rb b/Library/Homebrew/cmd/--env.rb
index 694b43207806b..a0c16eaafcd4c 100644
--- a/Library/Homebrew/cmd/--env.rb
+++ b/Library/Homebrew/cmd/--env.rb
@@ -36,7 +36,6 @@ def __env
     shell = if args.plain?
       nil
     elsif args.shell.nil?
-      # legacy behavior
       :bash unless $stdout.tty?
     elsif args.shell == "auto"
       Utils::Shell.parent || Utils::Shell.preferred
diff --git a/Library/Homebrew/cmd/info.rb b/Library/Homebrew/cmd/info.rb
index d914eb4977f2d..84873032359ba 100644
--- a/Library/Homebrew/cmd/info.rb
+++ b/Library/Homebrew/cmd/info.rb
@@ -105,11 +105,7 @@ def print_info
       args.named.each_with_index do |f, i|
         puts unless i.zero?
         begin
-          formula = if f.include?("/") || File.exist?(f)
-            Formulary.factory(f)
-          else
-            Formulary.find_with_priority(f)
-          end
+          Formulary.factory(f)
           if args.analytics?
             Utils::Analytics.formula_output(formula)
           else
diff --git a/Library/Homebrew/cmd/tap-pin.rb b/Library/Homebrew/cmd/tap-pin.rb
deleted file mode 100644
index b8e7a87365eeb..0000000000000
--- a/Library/Homebrew/cmd/tap-pin.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-# frozen_string_literal: true
-
-require "cli/parser"
-
-module Homebrew
-  module_function
-
-  def tap_pin_args
-    Homebrew::CLI::Parser.new do
-      hide_from_man_page!
-    end
-  end
-
-  def tap_pin
-    odisabled "the brew tap-pin command",
-              "fully-scoped user/tap/formula naming when installing and in dependency references"
-  end
-end
diff --git a/Library/Homebrew/cmd/tap-unpin.rb b/Library/Homebrew/cmd/tap-unpin.rb
deleted file mode 100644
index 2ec6e681a9096..0000000000000
--- a/Library/Homebrew/cmd/tap-unpin.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-# frozen_string_literal: true
-
-require "cli/parser"
-
-module Homebrew
-  module_function
-
-  def tap_unpin_args
-    Homebrew::CLI::Parser.new do
-      hide_from_man_page!
-    end
-  end
-
-  def tap_unpin
-    odisabled "the brew tap-unpin command",
-              "fully-scoped user/tap/formula naming when installing and in dependency references"
-  end
-end
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index df2481fb10f09..c1bf4ab05b9fb 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -216,7 +216,7 @@ def upgrade_formula(f)
   ensure
     # restore previous installation state if build failed
     begin
-      linked_kegs.each(&:link) unless f.installed?
+      linked_kegs.each(&:link) unless f.latest_version_installed?
     rescue
       nil
     end
diff --git a/Library/Homebrew/compat.rb b/Library/Homebrew/compat.rb
index a73aa184ef64c..79806737a5927 100644
--- a/Library/Homebrew/compat.rb
+++ b/Library/Homebrew/compat.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-require "compat/cask/dsl/version"
-require "compat/language/python"
-require "compat/requirements/macos_requirement"
+require "compat/extend/nil"
+require "compat/extend/string"
 require "compat/formula"
+require "compat/language/python"
 require "compat/os/mac" if OS.mac?
diff --git a/Library/Homebrew/compat/cask/dsl/version.rb b/Library/Homebrew/compat/cask/dsl/version.rb
deleted file mode 100644
index d2b4aa94cfb23..0000000000000
--- a/Library/Homebrew/compat/cask/dsl/version.rb
+++ /dev/null
@@ -1,23 +0,0 @@
-# frozen_string_literal: true
-
-module Cask
-  class DSL
-    class Version < ::String
-      module Compat
-        def dots_to_slashes
-          odisabled "#dots_to_slashes"
-        end
-
-        def hyphens_to_slashes
-          odisabled "#hyphens_to_slashes"
-        end
-
-        def underscores_to_slashes
-          odisabled "#underscores_to_slashes"
-        end
-      end
-
-      prepend Compat
-    end
-  end
-end
diff --git a/Library/Homebrew/compat/extend/nil.rb b/Library/Homebrew/compat/extend/nil.rb
new file mode 100644
index 0000000000000..0fa14795588dc
--- /dev/null
+++ b/Library/Homebrew/compat/extend/nil.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class NilClass
+  module Compat
+    def chuzzle
+      odeprecated "chuzzle", "chomp.presence"
+    end
+  end
+
+  prepend Compat
+end
diff --git a/Library/Homebrew/compat/extend/string.rb b/Library/Homebrew/compat/extend/string.rb
new file mode 100644
index 0000000000000..78baab5073ab0
--- /dev/null
+++ b/Library/Homebrew/compat/extend/string.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class String
+  module Compat
+    # String.chomp, but if result is empty: returns nil instead.
+    # Allows `chuzzle || foo` short-circuits.
+    def chuzzle
+      odeprecated "chuzzle", "chomp.presence"
+      s = chomp
+      s unless s.empty?
+    end
+  end
+
+  prepend Compat
+end
diff --git a/Library/Homebrew/compat/formula.rb b/Library/Homebrew/compat/formula.rb
index 66a6f8befb268..74caf081fbe43 100644
--- a/Library/Homebrew/compat/formula.rb
+++ b/Library/Homebrew/compat/formula.rb
@@ -3,10 +3,19 @@
 class Formula
   module Compat
     def installed?
-      # odeprecated "Formula#installed?",
-      #             "Formula#latest_version_installed? (or Formula#any_version_installed? )"
+      odeprecated "Formula#installed?",
+                  "Formula#latest_version_installed? (or Formula#any_version_installed? )"
       latest_version_installed?
     end
+
+    def prepare_patches
+      if respond_to?(:patches)
+        active_spec.add_legacy_patches(patches)
+        odeprecated "patches", "patch do"
+      end
+
+      super
+    end
   end
 
   prepend Compat
diff --git a/Library/Homebrew/compat/language/haskell.rb b/Library/Homebrew/compat/language/haskell.rb
index 0f961b1c347ab..bea5f40de9be8 100644
--- a/Library/Homebrew/compat/language/haskell.rb
+++ b/Library/Homebrew/compat/language/haskell.rb
@@ -5,7 +5,7 @@ module Haskell
     module Cabal
       module Compat
         def cabal_sandbox(options = {})
-          # odeprecated "Language::Haskell::Cabal.cabal_sandbox"
+          odeprecated "Language::Haskell::Cabal.cabal_sandbox"
 
           pwd = Pathname.pwd
           home = options[:home] || pwd
@@ -41,14 +41,14 @@ def cabal_sandbox(options = {})
         end
 
         def cabal_sandbox_add_source(*args)
-          # odeprecated "Language::Haskell::Cabal.cabal_sandbox_add_source"
+          odeprecated "Language::Haskell::Cabal.cabal_sandbox_add_source"
 
           system "cabal", "v1-sandbox", "add-source", *args
         end
 
         def cabal_install(*args)
-          # odeprecated "Language::Haskell::Cabal.cabal_install",
-          #             "cabal v2-install directly with std_cabal_v2_args"
+          odeprecated "Language::Haskell::Cabal.cabal_install",
+                      "cabal v2-install directly with std_cabal_v2_args"
 
           # cabal hardcodes 64 as the maximum number of parallel jobs
           # https://github.com/Homebrew/legacy-homebrew/issues/49509
@@ -64,13 +64,13 @@ def cabal_install(*args)
         end
 
         def cabal_configure(flags)
-          # odeprecated "Language::Haskell::Cabal.cabal_configure"
+          odeprecated "Language::Haskell::Cabal.cabal_configure"
 
           system "cabal", "v1-configure", flags
         end
 
         def cabal_install_tools(*tools)
-          # odeprecated "Language::Haskell::Cabal.cabal_install_tools"
+          odeprecated "Language::Haskell::Cabal.cabal_install_tools"
 
           # install tools sequentially, as some tools can depend on other tools
           tools.each { |tool| cabal_install tool }
@@ -81,8 +81,8 @@ def cabal_install_tools(*tools)
         end
 
         def install_cabal_package(*args, **options)
-          # odeprecated "Language::Haskell::Cabal.install_cabal_package",
-          #             "cabal v2-update directly followed by v2-install with std_cabal_v2_args"
+          odeprecated "Language::Haskell::Cabal.install_cabal_package",
+                      "cabal v2-update directly followed by v2-install with std_cabal_v2_args"
 
           cabal_sandbox do
             cabal_install_tools(*options[:using]) if options[:using]
diff --git a/Library/Homebrew/compat/language/python.rb b/Library/Homebrew/compat/language/python.rb
index 54784465ba5cd..1012e98dddf5c 100644
--- a/Library/Homebrew/compat/language/python.rb
+++ b/Library/Homebrew/compat/language/python.rb
@@ -5,6 +5,8 @@ module Python
     class << self
       module Compat
         def rewrite_python_shebang(python_path)
+          odeprecated "Language::Python.rewrite_python_shebang",
+                      "Utils::Shebang.rewrite_shebang and Shebang.python_shebang_rewrite_info(python_path)"
           Pathname.pwd.find do |f|
             Utils::Shebang.rewrite_shebang(Shebang.python_shebang_rewrite_info(python_path), f)
           end
diff --git a/Library/Homebrew/compat/os/mac.rb b/Library/Homebrew/compat/os/mac.rb
index af3863c86abcf..b9b6a0bf740f9 100644
--- a/Library/Homebrew/compat/os/mac.rb
+++ b/Library/Homebrew/compat/os/mac.rb
@@ -5,7 +5,7 @@ module Mac
     class << self
       module Compat
         def preferred_arch
-          # odeprecated "MacOS.preferred_arch", "Hardware::CPU.arch (or ideally let the compiler handle it)"
+          odeprecated "MacOS.preferred_arch", "Hardware::CPU.arch (or ideally let the compiler handle it)"
           if Hardware::CPU.is_64_bit?
             Hardware::CPU.arch_64_bit
           else
@@ -14,12 +14,12 @@ def preferred_arch
         end
 
         def tcc_db
-          # odeprecated "MacOS.tcc_db"
+          odeprecated "MacOS.tcc_db"
           @tcc_db ||= Pathname.new("/Library/Application Support/com.apple.TCC/TCC.db")
         end
 
         def pre_mavericks_accessibility_dotfile
-          # odeprecated "MacOS.pre_mavericks_accessibility_dotfile"
+          odeprecated "MacOS.pre_mavericks_accessibility_dotfile"
           @pre_mavericks_accessibility_dotfile ||= Pathname.new("/private/var/db/.AccessibilityAPIEnabled")
         end
       end
diff --git a/Library/Homebrew/compat/requirements/macos_requirement.rb b/Library/Homebrew/compat/requirements/macos_requirement.rb
deleted file mode 100644
index 3fe3208d94da6..0000000000000
--- a/Library/Homebrew/compat/requirements/macos_requirement.rb
+++ /dev/null
@@ -1,35 +0,0 @@
-# frozen_string_literal: true
-
-class MacOSRequirement < Requirement
-  module Compat
-    def initialize(tags = [], comparator: ">=")
-      if tags.first.respond_to?(:map)
-        versions, *rest = tags
-
-        versions = versions.map do |v|
-          next v if v.is_a?(Symbol)
-
-          sym = MacOS::Version.new(v).to_sym
-
-          odisabled "depends_on macos: #{v.inspect}",
-                    "depends_on macos: #{sym.inspect}"
-          sym
-        end
-
-        tags = [versions, *rest]
-      elsif !tags.empty? && !tags.first.is_a?(Symbol)
-        v, *rest = tags
-        sym = MacOS::Version.new(v).to_sym
-
-        odisabled "depends_on macos: #{v.inspect}",
-                  "depends_on macos: #{sym.inspect}"
-
-        tags = [sym, *rest]
-      end
-
-      super(tags, comparator: comparator)
-    end
-  end
-
-  prepend Compat
-end
diff --git a/Library/Homebrew/dev-cmd/audit.rb b/Library/Homebrew/dev-cmd/audit.rb
index 87faf0b725c24..94431b87ba65c 100644
--- a/Library/Homebrew/dev-cmd/audit.rb
+++ b/Library/Homebrew/dev-cmd/audit.rb
@@ -134,19 +134,8 @@ def audit
       end
     end
 
-    created_pr_comment = false
-    if new_formula && !new_formula_problem_lines.empty?
-      begin
-        created_pr_comment = true if GitHub.create_issue_comment(new_formula_problem_lines.join("\n"))
-      rescue *GitHub.api_errors => e
-        opoo "Unable to create issue comment: #{e.message}"
-      end
-    end
-
-    unless created_pr_comment
-      new_formula_problem_count += new_formula_problem_lines.size
-      puts new_formula_problem_lines.map { |s| "  #{s}" }
-    end
+    new_formula_problem_count += new_formula_problem_lines.size
+    puts new_formula_problem_lines.map { |s| "  #{s}" }
 
     total_problems_count = problem_count + new_formula_problem_count
     problem_plural = "#{total_problems_count} #{"problem".pluralize(total_problems_count)}"
diff --git a/Library/Homebrew/dev-cmd/irb.rb b/Library/Homebrew/dev-cmd/irb.rb
index e319acd972c2a..56c164ec5f241 100644
--- a/Library/Homebrew/dev-cmd/irb.rb
+++ b/Library/Homebrew/dev-cmd/irb.rb
@@ -38,7 +38,7 @@ def irb
 
     if args.examples?
       puts "'v8'.f # => instance of the v8 formula"
-      puts ":hub.f.installed?"
+      puts ":hub.f.latest_version_installed?"
       puts ":lua.f.methods - 1.methods"
       puts ":mpd.f.recursive_dependencies.reject(&:installed?)"
       return
diff --git a/Library/Homebrew/dev-cmd/pr-pull.rb b/Library/Homebrew/dev-cmd/pr-pull.rb
index 039f52cc2a54f..48495a2b5d093 100644
--- a/Library/Homebrew/dev-cmd/pr-pull.rb
+++ b/Library/Homebrew/dev-cmd/pr-pull.rb
@@ -60,7 +60,7 @@ def setup_git_environment!
     rescue FormulaUnavailableError
       nil
     else
-      if gnupg.installed?
+      if gnupg.any_version_installed?
         path = PATH.new(ENV.fetch("PATH"))
         path.prepend(gnupg.installed_prefix/"bin")
         ENV["PATH"] = path
diff --git a/Library/Homebrew/dev-cmd/pull.rb b/Library/Homebrew/dev-cmd/pull.rb
index 4f1f988569d0b..5950f72bea98e 100644
--- a/Library/Homebrew/dev-cmd/pull.rb
+++ b/Library/Homebrew/dev-cmd/pull.rb
@@ -56,7 +56,7 @@ def pull
         gnupg = Formula["gnupg"]
       rescue FormulaUnavailableError # rubocop:disable Lint/SuppressedException
       else
-        if gnupg.installed?
+        if gnupg.any_version_installed?
           path = PATH.new(ENV.fetch("PATH"))
           path.prepend(gnupg.installed_prefix/"bin")
           ENV["PATH"] = path
diff --git a/Library/Homebrew/extend/pathname.rb b/Library/Homebrew/extend/pathname.rb
index 98a8cfc1b191d..2837ff096e1c7 100644
--- a/Library/Homebrew/extend/pathname.rb
+++ b/Library/Homebrew/extend/pathname.rb
@@ -398,15 +398,6 @@ def ds_store?
     basename.to_s == ".DS_Store"
   end
 
-  # https://bugs.ruby-lang.org/issues/9915
-  if RUBY_VERSION == "2.0.0"
-    prepend Module.new {
-      def inspect
-        super.force_encoding(@path.encoding)
-      end
-    }
-  end
-
   def binary_executable?
     false
   end
diff --git a/Library/Homebrew/extend/string.rb b/Library/Homebrew/extend/string.rb
index a0dcb38776849..821902402175b 100644
--- a/Library/Homebrew/extend/string.rb
+++ b/Library/Homebrew/extend/string.rb
@@ -2,21 +2,6 @@
 
 require "active_support/core_ext/object/blank"
 
-class String
-  # String.chomp, but if result is empty: returns nil instead.
-  # Allows `chuzzle || foo` short-circuits.
-  # TODO: Deprecate.
-  def chuzzle
-    s = chomp
-    s unless s.empty?
-  end
-end
-
-class NilClass
-  # TODO: Deprecate.
-  def chuzzle; end
-end
-
 # Used by the inreplace function (in `utils.rb`).
 module StringInreplaceExtension
   attr_accessor :errors
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index ab90329020e28..9b62f60c85f42 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -2090,7 +2090,6 @@ def fetch_patches
   private
 
   def prepare_patches
-    active_spec.add_legacy_patches(patches) if respond_to?(:patches)
     patchlist.grep(DATAPatch) { |p| p.path = path }
   end
 
@@ -2171,7 +2170,10 @@ def method_added(method)
         raise "You cannot override Formula#brew in class #{name}"
       when :test
         define_method(:test_defined?) { true }
+      when :patches
+        odeprecated "a Formula#patches definition", "'patch do' block calls"
       when :options
+        odeprecated "a Formula#options definition", "'option do' block calls"
         instance = allocate
 
         specs.each do |spec|
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 18ed7cb437d28..7e8cc0ca235b4 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -589,7 +589,7 @@ def install_dependency(dep, inherited_options)
       linked_keg.unlink
     end
 
-    if df.installed?
+    if df.latest_version_installed?
       installed_keg = Keg.new(df.prefix)
       tmp_keg = Pathname.new("#{installed_keg}.tmp")
       installed_keg.rename(tmp_keg)
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index b01973fab6f54..8448a1298d895 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -205,21 +205,16 @@ def initialize(url)
     def load_file
       if url =~ %r{githubusercontent.com/[\w-]+/[\w-]+/[a-f0-9]{40}(/Formula)?/([\w+-.@]+).rb}
         formula_name = Regexp.last_match(2)
-        opoo <<~EOS
-          Unsupported installation from a commit URL!
-          Consider using `brew extract #{formula_name} ...` instead!"
-          This will extract your desired #{formula_name} version to a stable tap instead of
-          installing from a commit URL that cannnot receive updates or fixes!
-
-        EOS
+        odeprecated "Installation of #{formula_name} from a commit URL",
+                    "Use 'brew extract #{formula_name}' to stable tap."
       end
       HOMEBREW_CACHE_FORMULA.mkpath
       FileUtils.rm_f(path)
       curl_download url, to: path
       super
     rescue MethodDeprecatedError => e
-      if url =~ %r{github.com/([\w-]+)/homebrew-([\w-]+)/}
-        e.issues_url = "https://github.com/#{Regexp.last_match(1)}/homebrew-#{Regexp.last_match(2)}/issues/new"
+      if url =~ %r{github.com/([\w-]+)/([\w-]+)/}
+        e.issues_url = "https://github.com/#{Regexp.last_match(1)}/#{Regexp.last_match(2)}/issues/new"
       end
       raise
     end
@@ -483,20 +478,4 @@ def self.tap_paths(name, taps = Dir[HOMEBREW_LIBRARY/"Taps/*/*/"])
                     ]).find(&:file?)
     end.compact
   end
-
-  def self.find_with_priority(ref, spec = :stable)
-    possible_pinned_tap_formulae = tap_paths(ref, Dir["#{HOMEBREW_LIBRARY}/PinnedTaps/*/*/"]).map(&:realpath)
-    raise TapFormulaAmbiguityError.new(ref, possible_pinned_tap_formulae) if possible_pinned_tap_formulae.size > 1
-
-    if possible_pinned_tap_formulae.size == 1
-      selected_formula = factory(possible_pinned_tap_formulae.first, spec)
-      if core_path(ref).file?
-        odisabled "the brew tap-pin command",
-                  "fully-scoped user/tap/formula naming when installing and in dependency references"
-      end
-      selected_formula
-    else
-      factory(ref, spec)
-    end
-  end
 end
diff --git a/Library/Homebrew/language/python.rb b/Library/Homebrew/language/python.rb
index caaa6cb6a4e7e..581ee82ac0289 100644
--- a/Library/Homebrew/language/python.rb
+++ b/Library/Homebrew/language/python.rb
@@ -33,7 +33,7 @@ def self.each_python(build, &block)
         next if build.without? python_formula.to_s
 
         version = major_minor_version python
-        ENV["PYTHONPATH"] = if python_formula.installed?
+        ENV["PYTHONPATH"] = if python_formula.latest_version_installed?
           nil
         else
           homebrew_site_packages(python)
diff --git a/Library/Homebrew/patch.rb b/Library/Homebrew/patch.rb
index 1050e5bdf4947..03aea114e43ae 100644
--- a/Library/Homebrew/patch.rb
+++ b/Library/Homebrew/patch.rb
@@ -169,6 +169,7 @@ def inspect
 # Legacy patches have no checksum and are not cached.
 class LegacyPatch < ExternalPatch
   def initialize(strip, url)
+    odeprecated "legacy patches", "'patch do' blocks"
     super(strip)
     resource.url(url)
     resource.download_strategy = CurlDownloadStrategy
diff --git a/Library/Homebrew/requirements/java_requirement.rb b/Library/Homebrew/requirements/java_requirement.rb
index 1c324df27311c..6d7c66c73ceae 100644
--- a/Library/Homebrew/requirements/java_requirement.rb
+++ b/Library/Homebrew/requirements/java_requirement.rb
@@ -111,7 +111,7 @@ def possible_javas
     rescue FormulaUnavailableError
       nil
     end
-    javas << jdk.bin/"java" if jdk&.installed?
+    javas << jdk.bin/"java" if jdk&.latest_version_installed?
     javas << which("java")
     javas
   end
diff --git a/Library/Homebrew/software_spec.rb b/Library/Homebrew/software_spec.rb
index 0e31f23b9f8ff..72da2a2da1978 100644
--- a/Library/Homebrew/software_spec.rb
+++ b/Library/Homebrew/software_spec.rb
@@ -221,6 +221,7 @@ def needs(*standards)
     end
   end
 
+  # TODO
   def add_legacy_patches(list)
     list = Patch.normalize_legacy_patches(list)
     list.each { |p| p.owner = self }
diff --git a/Library/Homebrew/test/formula_spec.rb b/Library/Homebrew/test/formula_spec.rb
index 6daf45f1ab800..f7c13c6cebb2b 100644
--- a/Library/Homebrew/test/formula_spec.rb
+++ b/Library/Homebrew/test/formula_spec.rb
@@ -644,25 +644,6 @@
     expect(f.head.version).to eq(Version.create("HEAD-5658946"))
   end
 
-  specify "legacy options" do
-    f = formula do
-      url "foo-1.0"
-
-      def options
-        [
-          ["--foo", "desc"],
-          ["--bar", "desc"],
-        ]
-      end
-
-      option("baz")
-    end
-
-    expect(f).to have_option_defined("foo")
-    expect(f).to have_option_defined("bar")
-    expect(f).to have_option_defined("baz")
-  end
-
   specify "#desc" do
     f = formula do
       desc "a formula"
@@ -673,23 +654,6 @@ def options
     expect(f.desc).to eq("a formula")
   end
 
-  specify "#test_defined?" do
-    f1 = formula do
-      url "foo-1.0"
-
-      def test
-        # do nothing
-      end
-    end
-
-    f2 = formula do
-      url "foo-1.0"
-    end
-
-    expect(f1).to have_test_defined
-    expect(f2).not_to have_test_defined
-  end
-
   specify "test fixtures" do
     f1 = formula do
       url "foo-1.0"
diff --git a/Library/Homebrew/test/formulary_spec.rb b/Library/Homebrew/test/formulary_spec.rb
index 157b608050206..5458fc6e024b6 100644
--- a/Library/Homebrew/test/formulary_spec.rb
+++ b/Library/Homebrew/test/formulary_spec.rb
@@ -234,22 +234,6 @@ class Wrong#{described_class.class_s(formula_name)} < Formula
     end
   end
 
-  describe "::find_with_priority" do
-    let(:core_path) { CoreTap.new.formula_dir/"#{formula_name}.rb" }
-    let(:tap) { Tap.new("homebrew", "foo") }
-    let(:tap_path) { tap.path/"#{formula_name}.rb" }
-
-    before do
-      core_path.write formula_content
-      tap_path.write formula_content
-    end
-
-    it "prioritizes core Formulae" do
-      formula = described_class.find_with_priority(formula_name)
-      expect(formula.path).to eq(core_path)
-    end
-  end
-
   describe "::core_path" do
     it "returns the path to a Formula in the core tap" do
       name = "foo-bar"
diff --git a/Library/Homebrew/test/patch_spec.rb b/Library/Homebrew/test/patch_spec.rb
index 463894ff4c651..fff1fc48b287f 100644
--- a/Library/Homebrew/test/patch_spec.rb
+++ b/Library/Homebrew/test/patch_spec.rb
@@ -74,74 +74,6 @@
       expect(subject.patch_files.count).to eq(7)
     end
   end
-
-  describe "#normalize_legacy_patches" do
-    it "can create a patch from a single string" do
-      patches = described_class.normalize_legacy_patches("https://brew.sh/patch.diff")
-      expect(patches.length).to eq(1)
-      expect(patches.first.strip).to eq(:p1)
-    end
-
-    it "can create patches from an array" do
-      patches = described_class.normalize_legacy_patches(
-        %w[https://brew.sh/patch1.diff https://brew.sh/patch2.diff],
-      )
-
-      expect(patches.length).to eq(2)
-      expect(patches.first.strip).to eq(:p1)
-      expect(patches.second.strip).to eq(:p1)
-    end
-
-    it "can create patches from a :p0 hash" do
-      patches = described_class.normalize_legacy_patches(
-        p0: "https://brew.sh/patch.diff",
-      )
-
-      expect(patches.length).to eq(1)
-      expect(patches.first.strip).to eq(:p0)
-    end
-
-    it "can create patches from a :p1 hash" do
-      patches = described_class.normalize_legacy_patches(
-        p1: "https://brew.sh/patch.diff",
-      )
-
-      expect(patches.length).to eq(1)
-      expect(patches.first.strip).to eq(:p1)
-    end
-
-    it "can create patches from a mixed hash" do
-      patches = described_class.normalize_legacy_patches(
-        p1: "https://brew.sh/patch1.diff",
-        p0: "https://brew.sh/patch0.diff",
-      )
-
-      expect(patches.length).to eq(2)
-      expect(patches.count { |p| p.strip == :p0 }).to eq(1)
-      expect(patches.count { |p| p.strip == :p1 }).to eq(1)
-    end
-
-    it "can create patches from a mixed hash with array" do
-      patches = described_class.normalize_legacy_patches(
-        p1: [
-          "https://brew.sh/patch10.diff",
-          "https://brew.sh/patch11.diff",
-        ],
-        p0: [
-          "https://brew.sh/patch00.diff",
-          "https://brew.sh/patch01.diff",
-        ],
-      )
-
-      expect(patches.length).to eq(4)
-      expect(patches.count { |p| p.strip == :p0 }).to eq(2)
-      expect(patches.count { |p| p.strip == :p1 }).to eq(2)
-    end
-
-    it "returns an empty array if given nil" do
-      expect(described_class.normalize_legacy_patches(nil)).to be_empty
-    end
-  end
 end
 
 describe EmbeddedPatch do
diff --git a/Library/Homebrew/test/patching_spec.rb b/Library/Homebrew/test/patching_spec.rb
index b921bb5d76c53..ffdf1027dc5ae 100644
--- a/Library/Homebrew/test/patching_spec.rb
+++ b/Library/Homebrew/test/patching_spec.rb
@@ -65,16 +65,6 @@ def formula(name = "formula_name", path: Formulary.core_path(name), spec: :stabl
     end
   end
 
-  specify "single_patch" do
-    expect(
-      formula do
-        def patches
-          PATCH_URL_A
-        end
-      end,
-    ).to be_patched
-  end
-
   specify "single_patch_dsl" do
     expect(
       formula do
@@ -199,46 +189,6 @@ def patches
     ).to be_patched
   end
 
-  specify "patch_p0" do
-    expect(
-      formula do
-        def patches
-          { p0: PATCH_URL_B }
-        end
-      end,
-    ).to be_patched
-  end
-
-  specify "patch_array" do
-    expect(
-      formula do
-        def patches
-          [PATCH_URL_A]
-        end
-      end,
-    ).to be_patched
-  end
-
-  specify "patch_hash" do
-    expect(
-      formula do
-        def patches
-          { p1: PATCH_URL_A }
-        end
-      end,
-    ).to be_patched
-  end
-
-  specify "patch_hash_array" do
-    expect(
-      formula do
-        def patches
-          { p1: [PATCH_URL_A] }
-        end
-      end,
-    ).to be_patched
-  end
-
   specify "patch_string" do
     expect(formula { patch PATCH_A_CONTENTS }).to be_patched
   end
@@ -247,26 +197,6 @@ def patches
     expect(formula { patch :p0, PATCH_B_CONTENTS }).to be_patched
   end
 
-  specify "patch_data_constant" do
-    expect(
-      formula("test", path: Pathname.new(__FILE__).expand_path) do
-        def patches
-          :DATA
-        end
-      end,
-    ).to be_patched
-  end
-
-  specify "single_patch_missing_apply_fail" do
-    expect(
-      formula do
-        def patches
-          TESTBALL_PATCHES_URL
-        end
-      end,
-    ).to miss_apply
-  end
-
   specify "single_patch_dsl_missing_apply_fail" do
     expect(
       formula do
diff --git a/Library/Homebrew/utils/github.rb b/Library/Homebrew/utils/github.rb
index 1768ed6b567f0..3b82876072a86 100644
--- a/Library/Homebrew/utils/github.rb
+++ b/Library/Homebrew/utils/github.rb
@@ -14,8 +14,6 @@ module GitHub
   ALL_SCOPES_URL = Formatter.url(
     "https://github.com/settings/tokens/new?scopes=#{ALL_SCOPES.join(",")}&description=Homebrew",
   ).freeze
-  PR_ENV_KEY = "HOMEBREW_NEW_FORMULA_PULL_REQUEST_URL"
-  PR_ENV = ENV[PR_ENV_KEY]
 
   class Error < RuntimeError
     attr_reader :github_message
@@ -396,37 +394,6 @@ def search(entity, *queries, **qualifiers)
     open_api(uri) { |json| json.fetch("items", []) }
   end
 
-  def create_issue_comment(body)
-    return false unless PR_ENV
-
-    _, user, repo, pr = *PR_ENV.match(HOMEBREW_PULL_OR_COMMIT_URL_REGEX)
-    if !user || !repo || !pr
-      opoo <<-EOS.undent
-        #{PR_ENV_KEY} set but regex matched:
-        user: #{user.inspect}, repo: #{repo.inspect}, pr: #{pr.inspect}
-      EOS
-      return false
-    end
-
-    url = "#{API_URL}/repos/#{user}/#{repo}/issues/#{pr}/comments"
-    data = { "body" => body }
-    if issue_comment_exists?(user, repo, pr, body)
-      ohai "Skipping: identical comment exists on #{PR_ENV}"
-      return true
-    end
-
-    scopes = CREATE_ISSUE_FORK_OR_PR_SCOPES
-    open_api(url, data: data, scopes: scopes)
-  end
-
-  def issue_comment_exists?(user, repo, pr, body)
-    url = "#{API_URL}/repos/#{user}/#{repo}/issues/#{pr}/comments"
-    comments = open_api(url)
-    return unless comments
-
-    comments.any? { |comment| comment["body"].eql?(body) }
-  end
-
   def dispatch_event(user, repo, event, **payload)
     url = "#{API_URL}/repos/#{user}/#{repo}/dispatches"
     open_api(url, data:           { event_type: event, client_payload: payload },