diff --git a/Library/Homebrew/dev-cmd/bump-cask-pr.rb b/Library/Homebrew/dev-cmd/bump-cask-pr.rb
index 1a70fed47f082cd80c0170fccb51e864319ac0a0..7a4b74e6bbd85cbc5cd349ec62797fe903513093 100644
--- a/Library/Homebrew/dev-cmd/bump-cask-pr.rb
+++ b/Library/Homebrew/dev-cmd/bump-cask-pr.rb
@@ -77,8 +77,8 @@ module Homebrew
     old_hash = cask.sha256.to_s
 
     tap_full_name = cask.tap&.full_name
-    origin_branch = Utils::Git.origin_branch(cask.tap.path) if cask.tap
-    origin_branch ||= "origin/master"
+    default_remote_branch = cask.tap.path.git_origin_branch if cask.tap
+    default_remote_branch ||= "master"
     previous_branch = "-"
 
     check_open_pull_requests(cask, tap_full_name, args: args)
@@ -200,7 +200,7 @@ module Homebrew
     pr_info = {
       sourcefile_path: cask.sourcefile_path,
       old_contents:    old_contents,
-      origin_branch:   origin_branch,
+      remote_branch:   default_remote_branch,
       branch_name:     "bump-#{cask.token}-#{new_version.tr(",:", "-")}",
       commit_message:  "Update #{cask.token} from #{old_version} to #{new_version}",
       previous_branch: previous_branch,
diff --git a/Library/Homebrew/dev-cmd/bump-formula-pr.rb b/Library/Homebrew/dev-cmd/bump-formula-pr.rb
index dffc4dcdf35fce1c1857e6923180a2b33c97afd1..19e28f8f3298bcf9699c11ca9b9258381b23b980 100644
--- a/Library/Homebrew/dev-cmd/bump-formula-pr.rb
+++ b/Library/Homebrew/dev-cmd/bump-formula-pr.rb
@@ -84,44 +84,38 @@ module Homebrew
   end
 
   def use_correct_linux_tap(formula, args:)
-    if OS.linux? && formula.tap.core_tap?
-      tap_full_name = formula.tap.full_name.gsub("linuxbrew", "homebrew")
-      homebrew_core_url = "https://github.com/#{tap_full_name}"
-      homebrew_core_remote = "homebrew"
-      homebrew_core_branch = "master"
-      origin_branch = "#{homebrew_core_remote}/#{homebrew_core_branch}"
-      previous_branch = Utils.popen_read("git -C \"#{formula.tap.path}\" symbolic-ref -q --short HEAD").chomp
-      previous_branch = "master" if previous_branch.empty?
-      formula_path = formula.path.to_s[%r{(Formula/.*)}, 1]
-
-      if args.dry_run? || args.write?
-        ohai "git remote add #{homebrew_core_remote} #{homebrew_core_url}"
-        ohai "git fetch #{homebrew_core_remote} #{homebrew_core_branch}"
-        ohai "git cat-file -e #{origin_branch}:#{formula_path}"
-        ohai "git checkout #{origin_branch}"
-        return tap_full_name, origin_branch, previous_branch
-      else
-        formula.path.parent.cd do
-          unless Utils.popen_read("git remote -v").match?(%r{^homebrew.*Homebrew/homebrew-core.*$})
-            ohai "Adding #{homebrew_core_remote} remote"
-            safe_system "git", "remote", "add", homebrew_core_remote, homebrew_core_url
-          end
-          ohai "Fetching #{origin_branch}"
-          safe_system "git", "fetch", homebrew_core_remote, homebrew_core_branch
-          if quiet_system "git", "cat-file", "-e", "#{origin_branch}:#{formula_path}"
-            ohai "#{formula.full_name} exists in #{origin_branch}"
-            safe_system "git", "checkout", origin_branch
-            return tap_full_name, origin_branch, previous_branch
-          end
-        end
-      end
+    default_origin_branch = formula.tap.path.git_origin_branch if formula.tap
+
+    return formula.tap&.full_name, "origin", default_origin_branch, "-" if !OS.linux? || !formula.tap.core_tap?
+
+    tap_full_name = formula.tap.full_name.gsub("linuxbrew", "homebrew")
+    homebrew_core_url = "https://github.com/#{tap_full_name}"
+    homebrew_core_remote = "homebrew"
+    previous_branch = formula.tap.path.git_branch || "master"
+    formula_path = formula.path.relative_path_from(formula.tap.path)
+    full_origin_branch = "#{homebrew_core_remote}/#{default_origin_branch}"
+
+    if args.dry_run? || args.write?
+      ohai "git remote add #{homebrew_core_remote} #{homebrew_core_url}"
+      ohai "git fetch #{homebrew_core_remote} HEAD #{default_origin_branch}"
+      ohai "git cat-file -e #{full_origin_branch}:#{formula_path}"
+      ohai "git checkout #{full_origin_branch}"
+      return tap_full_name, homebrew_core_remote, default_origin_branch, previous_branch
     end
-    if formula.tap
-      origin_branch = Utils.popen_read("git", "-C", formula.tap.path.to_s, "symbolic-ref", "-q", "--short",
-                                       "refs/remotes/origin/HEAD").chomp.presence
+
+    formula.tap.path.cd do
+      unless Utils.popen_read("git remote -v").match?(%r{^homebrew.*Homebrew/homebrew-core.*$})
+        ohai "Adding #{homebrew_core_remote} remote"
+        safe_system "git", "remote", "add", homebrew_core_remote, homebrew_core_url
+      end
+      ohai "Fetching remote #{homebrew_core_remote}"
+      safe_system "git", "fetch", homebrew_core_remote, "HEAD", default_origin_branch
+      if quiet_system "git", "cat-file", "-e", "#{full_origin_branch}:#{formula_path}"
+        ohai "#{formula.full_name} exists in #{full_origin_branch}"
+        safe_system "git", "checkout", full_origin_branch
+        return tap_full_name, homebrew_core_remote, default_origin_branch, previous_branch
+      end
     end
-    origin_branch ||= "origin/master"
-    [formula.tap&.full_name, origin_branch, "-"]
   end
 
   def bump_formula_pr
@@ -142,7 +136,7 @@ module Homebrew
 
     odie "This formula is disabled!" if formula.disabled?
 
-    tap_full_name, origin_branch, previous_branch = use_correct_linux_tap(formula, args: args)
+    tap_full_name, remote, remote_branch, previous_branch = use_correct_linux_tap(formula, args: args)
     check_open_pull_requests(formula, tap_full_name, args: args)
 
     new_version = args.version
@@ -355,7 +349,8 @@ module Homebrew
       sourcefile_path:  formula.path,
       old_contents:     old_contents,
       additional_files: alias_rename,
-      origin_branch:    origin_branch,
+      remote:           remote,
+      remote_branch:    remote_branch,
       branch_name:      "bump-#{formula.name}-#{new_formula_version}",
       commit_message:   "#{formula.name} #{new_formula_version}",
       previous_branch:  previous_branch,
diff --git a/Library/Homebrew/dev-cmd/pr-pull.rb b/Library/Homebrew/dev-cmd/pr-pull.rb
index 8a0e93f946f15212fcdd53df7154c69c9edc9b5d..f866da3b9d0e4c514b3a3be317ad7dbece538970 100644
--- a/Library/Homebrew/dev-cmd/pr-pull.rb
+++ b/Library/Homebrew/dev-cmd/pr-pull.rb
@@ -385,11 +385,8 @@ module Homebrew
       _, user, repo, pr = *url_match
       odie "Not a GitHub pull request: #{arg}" unless pr
 
-      current_branch = tap.path.git_branch
-      origin_branch = Utils::Git.origin_branch(tap.path).split("/").last
-
-      if current_branch != origin_branch || args.branch_okay? || args.clean?
-        opoo "Current branch is #{current_branch}: do you need to pull inside #{origin_branch}?"
+      if !tap.path.git_default_origin_branch? || args.branch_okay? || args.clean?
+        opoo "Current branch is #{tap.path.git_branch}: do you need to pull inside #{tap.path.git_origin_branch}?"
       end
 
       ohai "Fetching #{tap} pull request ##{pr}"
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 74c9aca8cd58b2f3d7a2a459822083abd516286c..3199df2ac5f87f2063e3f8d42456a145410410a3 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -572,16 +572,9 @@ module Homebrew
         return unless Utils::Git.available?
 
         commands = Tap.map do |tap|
-          next unless tap.path.git?
-          next if tap.path.git_origin.blank?
+          next if tap.path.git_default_origin_branch?
 
-          branch = tap.path.git_branch
-          next if branch.blank?
-
-          origin_branch = Utils::Git.origin_branch(tap.path)&.split("/")&.last
-          next if origin_branch == branch
-
-          "git -C $(brew --repo #{tap.name}) checkout #{origin_branch}"
+          "git -C $(brew --repo #{tap.name}) checkout #{tap.path.git_origin_branch}"
         end.compact
 
         return if commands.blank?
diff --git a/Library/Homebrew/extend/git_repository.rb b/Library/Homebrew/extend/git_repository.rb
index 067f518bbfcaa5dfae393d8a1672aeecad658ee9..09c18ae1f28e189cf080ca521d2dcaee75827781 100644
--- a/Library/Homebrew/extend/git_repository.rb
+++ b/Library/Homebrew/extend/git_repository.rb
@@ -63,6 +63,21 @@ module GitRepositoryExtension
     Utils.popen_read("git", "rev-parse", "--abbrev-ref", "HEAD", chdir: self).chomp.presence
   end
 
+  # Gets the name of the default origin HEAD branch.
+  sig { returns(T.nilable(String)) }
+  def git_origin_branch
+    return unless git? && Utils::Git.available?
+
+    Utils.popen_read("git", "symbolic-ref", "-q", "--short", "refs/remotes/origin/HEAD", chdir: self)
+         .chomp.presence&.split("/")&.last
+  end
+
+  # Returns true if the repository's current branch matches the default origin branch.
+  sig { returns(T.nilable(T::Boolean)) }
+  def git_default_origin_branch?
+    git_origin_branch == git_branch
+  end
+
   # Returns the date of the last commit, in YYYY-MM-DD format.
   sig { returns(T.nilable(String)) }
   def git_last_commit_date
diff --git a/Library/Homebrew/utils/git.rb b/Library/Homebrew/utils/git.rb
index bb8deabe5578d1533c759b7b6014ca90588cc149..875bfea3542a90e1d44edf05673ce659f92ac0b4 100644
--- a/Library/Homebrew/utils/git.rb
+++ b/Library/Homebrew/utils/git.rb
@@ -135,8 +135,8 @@ module Utils
     end
 
     def origin_branch(repo)
-      Utils.popen_read(git, "-C", repo, "symbolic-ref", "-q", "--short",
-                       "refs/remotes/origin/HEAD").chomp.presence
+      odeprecated "Utils::Git.origin_branch(repo)", "Pathname(repo).git_origin_branch"
+      Pathname(repo).extend(GitRepositoryExtension).git_origin_branch
     end
 
     def current_branch(repo)
diff --git a/Library/Homebrew/utils/github.rb b/Library/Homebrew/utils/github.rb
index 8aeb60a21a7e57fff65b347970ae677829a773b1..c58974816834b55624ca00b05b284cb7457dcc78 100644
--- a/Library/Homebrew/utils/github.rb
+++ b/Library/Homebrew/utils/github.rb
@@ -679,7 +679,8 @@ module GitHub
     sourcefile_path = info[:sourcefile_path]
     old_contents = info[:old_contents]
     additional_files = info[:additional_files] || []
-    origin_branch = info[:origin_branch]
+    remote = info[:remote] || "origin"
+    remote_branch = info[:remote_branch]
     branch = info[:branch_name]
     commit_message = info[:commit_message]
     previous_branch = info[:previous_branch]
@@ -688,7 +689,6 @@ module GitHub
     pr_message = info[:pr_message]
 
     sourcefile_path.parent.cd do
-      _, base_branch = origin_branch.split("/")
       git_dir = Utils.popen_read("git rev-parse --git-dir").chomp
       shallow = !git_dir.empty? && File.exist?("#{git_dir}/shallow")
       changed_files = [sourcefile_path]
@@ -698,12 +698,12 @@ module GitHub
         ohai "try to fork repository with GitHub API" unless args.no_fork?
         ohai "git fetch --unshallow origin" if shallow
         ohai "git add #{changed_files.join(" ")}"
-        ohai "git checkout --no-track -b #{branch} #{origin_branch}"
+        ohai "git checkout --no-track -b #{branch} #{remote}/#{remote_branch}"
         ohai "git commit --no-edit --verbose --message='#{commit_message}'" \
              " -- #{changed_files.join(" ")}"
         ohai "git push --set-upstream $HUB_REMOTE #{branch}:#{branch}"
         ohai "git checkout --quiet #{previous_branch}"
-        ohai "create pull request with GitHub API (base branch: #{base_branch})"
+        ohai "create pull request with GitHub API (base branch: #{remote_branch})"
       else
 
         unless args.commit?
@@ -723,7 +723,7 @@ module GitHub
         end
 
         safe_system "git", "add", *changed_files
-        safe_system "git", "checkout", "--no-track", "-b", branch, origin_branch unless args.commit?
+        safe_system "git", "checkout", "--no-track", "-b", branch, "#{remote}/#{remote_branch}" unless args.commit?
         safe_system "git", "commit", "--no-edit", "--verbose",
                     "--message=#{commit_message}",
                     "--", *changed_files
@@ -746,7 +746,7 @@ module GitHub
 
         begin
           url = GitHub.create_pull_request(tap_full_name, commit_message,
-                                           "#{username}:#{branch}", base_branch, pr_message)["html_url"]
+                                           "#{username}:#{branch}", remote_branch, pr_message)["html_url"]
           if args.no_browse?
             puts url
           else