@@ -168,7 +168,7 @@ other hosts; this does not substitute for their native lock-contention tests.
 | --- | --- | --- | --- |
 | `app status` | None | None | Returns app/session state such as headless mode, page, and supported UI actions. |
 | `app show` | None | None | Shows and focuses the window when a GUI session exists. |
-| `app navigate` | `--page <page>` | `--manager <id>`, `--help-attachment <path>` | Valid pages include `discover`, `updates`, `installed`, `bundles`, `catalog`, `catalog-editor`, `settings`, `managers`, `own-log`, `manager-log`, `operation-history`, `help`, `release-notes`, and `about`. `catalog` and `catalog-editor` require Enable Software Catalog in Experimental settings and developer options, followed by an application restart. |
+| `app navigate` | `--page <page>` | `--manager <id>`, `--help-attachment <path>` | Valid pages include `discover`, `updates`, `installed`, `bundles`, `catalog`, `catalog-editor`, `git-repositories`, `settings`, `managers`, `own-log`, `manager-log`, `operation-history`, `help`, `release-notes`, and `about`. `catalog` and `catalog-editor` require Enable Software Catalog in Experimental settings and developer options, followed by an application restart. `git-repositories` requires the Git Repositories extension to be turned on in Settings, under Extensions; no restart is needed. |
 | `app quit` | None | None | Gracefully shuts down the selected session, including headless daemons. |
 
 ### Operations
 
@@ -111,6 +111,143 @@
   "Requires a machine-wide SoftwareCatalog.json file and an application restart.": "Requires a machine-wide SoftwareCatalog.json file and an application restart.",
   "Software Catalog is disabled": "Software Catalog is disabled",
   "Enable Software Catalog in Experimental settings and developer options, then restart UniGetUI.": "Enable Software Catalog in Experimental settings and developer options, then restart UniGetUI.",
+  "Git Repositories": "Git Repositories",
+  "Worktrees": "Worktrees",
+  "Only when asked": "Only when asked",
+  "Every 15 minutes": "Every 15 minutes",
+  "Every 30 minutes": "Every 30 minutes",
+  "Every hour": "Every hour",
+  "Every 4 hours": "Every 4 hours",
+  "Git was not found": "Git was not found",
+  "Install Git and make sure it is on the PATH, then restart UniGetUI.": "Install Git and make sure it is on the PATH, then restart UniGetUI.",
+  "{0} git clones were added": "{0} git clones were added",
+  "Choose git clones, or folders that contain them": "Choose git clones, or folders that contain them",
+  "No git clones were found in {0}": "No git clones were found in {0}",
+  "No git clones were found in the chosen folders": "No git clones were found in the chosen folders",
+  "Clones are looked for in the chosen folders and two levels of subfolders.": "Clones are looked for in the chosen folders and two levels of subfolders.",
+  "Every git clone found is already in the list": "Every git clone found is already in the list",
+  "1 git clone was added": "1 git clone was added",
+  "Pick a clone to keep up to date, or a folder such as your dev folder to add every clone in it": "Pick a clone to keep up to date, or a folder such as your dev folder to add every clone in it",
+  "{0} is not a git repository": "{0} is not a git repository",
+  "{0} is already in the list": "{0} is already in the list",
+  "Added the main clone of this worktree": "Added the main clone of this worktree",
+  "{0} is a worktree of {1}, so {1} was added instead.": "{0} is a worktree of {1}, so {1} was added instead.",
+  "UniGetUI keeps this clone current on the branch below. Leave it empty to follow the remote's default branch.": "UniGetUI keeps this clone current on the branch below. Leave it empty to follow the remote's default branch.",
+  "Branch to keep current": "Branch to keep current",
+  "{0} repositories could not be updated": "{0} repositories could not be updated",
+  "{0} repositories updated": "{0} repositories updated",
+  "{0} were left alone: see their status for why.": "{0} were left alone: see their status for why.",
+  "Every repository is up to date": "Every repository is up to date",
+  "Could not list the worktrees of {0}": "Could not list the worktrees of {0}",
+  "Could not prune the worktrees of {0}": "Could not prune the worktrees of {0}",
+  "The folder {0} will be deleted.": "The folder {0} will be deleted.",
+  "It has changed or untracked files. They will be lost.": "It has changed or untracked files. They will be lost.",
+  "Its branch has commits that are not on the default branch. Keep the branch to keep them.": "Its branch has commits that are not on the default branch. Keep the branch to keep them.",
+  "Also delete the branch {0}": "Also delete the branch {0}",
+  "Remove this worktree?": "Remove this worktree?",
+  "Could not remove the worktree {0}": "Could not remove the worktree {0}",
+  "Not checked yet": "Not checked yet",
+  "1 commit behind": "1 commit behind",
+  "{0} commits behind": "{0} commits behind",
+  "1 local commit not on the remote": "1 local commit not on the remote",
+  "{0} local commits not on the remote": "{0} local commits not on the remote",
+  "Diverged from {0}": "Diverged from {0}",
+  "Has local changes": "Has local changes",
+  "On {0} instead of {1}": "On {0} instead of {1}",
+  "No branch checked out": "No branch checked out",
+  "No remote branch to follow": "No remote branch to follow",
+  "Could not be checked": "Could not be checked",
+  "Check this repository to compare it with its remote.": "Check this repository to compare it with its remote.",
+  "Level with {0}.": "Level with {0}.",
+  "Updating fast-forwards it to {0}.": "Updating fast-forwards it to {0}.",
+  "It has commits that are not on {0}, so it is not updated: that would need a merge.": "It has commits that are not on {0}, so it is not updated: that would need a merge.",
+  "Tracked files have been changed, so it is not updated. Commit, stash or discard them first.": "Tracked files have been changed, so it is not updated. Commit, stash or discard them first.",
+  "Only a clone checked out on {0} is updated.": "Only a clone checked out on {0} is updated.",
+  "It has no remote, or its remote has no main or master branch. You can choose the branch to follow.": "It has no remote, or its remote has no main or master branch. You can choose the branch to follow.",
+  "detached": "detached",
+  "Checked at {0}": "Checked at {0}",
+  "1 worktree": "1 worktree",
+  "{0} worktrees": "{0} worktrees",
+  "detached at {0}": "detached at {0}",
+  "Last commit {0}": "Last commit {0}",
+  "1 commit not on the default branch": "1 commit not on the default branch",
+  "{0} commits not on the default branch": "{0} commits not on the default branch",
+  "Locked": "Locked",
+  "Locked: {0}": "Locked: {0}",
+  "Keep your main clones up to date on their default branch, and clean up their worktrees and branches.": "Keep your main clones up to date on their default branch, and clean up their worktrees and branches.",
+  "Add repository": "Add repository",
+  "Fetch every repository and compare it with its remote": "Fetch every repository and compare it with its remote",
+  "Check all": "Check all",
+  "Fetch every repository and fast-forward the ones that are only behind": "Fetch every repository and fast-forward the ones that are only behind",
+  "Check automatically:": "Check automatically:",
+  "Check automatically": "Check automatically",
+  "Only clones on their default branch, with no local changes and no commits of their own, are fast-forwarded.": "Only clones on their default branch, with no local changes and no commits of their own, are fast-forwarded.",
+  "Update after checking": "Update after checking",
+  "Check": "Check",
+  "Open folder": "Open folder",
+  "Choose the branch to keep current": "Choose the branch to keep current",
+  "Remove from the list": "Remove from the list",
+  "No repositories yet": "No repositories yet",
+  "Add the main clones you keep on main or master. UniGetUI fetches them and fast-forwards the ones that are only behind, never touching local work.": "Add the main clones you keep on main or master. UniGetUI fetches them and fast-forwards the ones that are only behind, never touching local work.",
+  "Forget the worktrees whose folder was deleted": "Forget the worktrees whose folder was deleted",
+  "Prune missing": "Prune missing",
+  "Main clone": "Main clone",
+  "Everything committed on it is on the default branch": "Everything committed on it is on the default branch",
+  "Merged": "Merged",
+  "Its remote branch was deleted, as after a merged pull request": "Its remote branch was deleted, as after a merged pull request",
+  "Remote branch deleted": "Remote branch deleted",
+  "Has changed or untracked files": "Has changed or untracked files",
+  "Looking for changed files...": "Looking for changed files...",
+  "1 clone": "1 clone",
+  "Enable Git Repositories": "Enable Git Repositories",
+  "Extensions": "Extensions",
+  "Fetches your main clones, fast-forwards their default branch, and helps you remove leftover worktrees and branches.": "Fetches your main clones, fast-forwards their default branch, and helps you remove leftover worktrees and branches.",
+  "Found {0}": "Found {0}",
+  "Git": "Git",
+  "Git was not found. Install it from Discover Packages, then come back to this page.": "Git was not found. Install it from Discover Packages, then come back to this page.",
+  "Keep your main git clones up to date and clean up leftover worktrees and branches": "Keep your main git clones up to date and clean up leftover worktrees and branches",
+  "Looking for Git...": "Looking for Git...",
+  "No clones yet": "No clones yet",
+  "Off": "Off",
+  "On": "On",
+  "Optional tools that go beyond package management": "Optional tools that go beyond package management",
+  "Preferences": "Preferences",
+  "Requirements": "Requirements",
+  "Turn it on in Settings, under Extensions.": "Turn it on in Settings, under Extensions.",
+  "{0} behind": "{0} behind",
+  "{0} clones": "{0} clones",
+  "Check for new commits automatically": "Check for new commits automatically",
+  "Choose the clones to keep up to date": "Choose the clones to keep up to date",
+  "Git Repositories is turned off": "Git Repositories is turned off",
+  "Open Git Repositories": "Open Git Repositories",
+  "Update clones after checking": "Update clones after checking",
+  "Branches": "Branches",
+  "Checked out in {0}": "Checked out in {0}",
+  "Could not delete the branch {0}": "Could not delete the branch {0}",
+  "Could not list the branches of {0}": "Could not list the branches of {0}",
+  "Default branch": "Default branch",
+  "Delete merged": "Delete merged",
+  "Delete the branches whose commits are all on the default branch": "Delete the branches whose commits are all on the default branch",
+  "Delete this branch?": "Delete this branch?",
+  "Delete {0} merged branches?": "Delete {0} merged branches?",
+  "Drag to resize": "Drag to resize",
+  "Everything committed on these branches is already on the default branch, so nothing is lost:": "Everything committed on these branches is already on the default branch, so nothing is lost:",
+  "Git repositories": "Git repositories",
+  "In sync with {0}": "In sync with {0}",
+  "It does not track a remote branch": "It does not track a remote branch",
+  "It has commits that are not on the default branch. They will be lost unless they were pushed.": "It has commits that are not on the default branch. They will be lost unless they were pushed.",
+  "It has commits that were never pushed to {0}.": "It has commits that were never pushed to {0}.",
+  "Local only": "Local only",
+  "Open the worktree it is checked out in": "Open the worktree it is checked out in",
+  "Read them again from git": "Read them again from git",
+  "Select a repository to see its worktrees and branches": "Select a repository to see its worktrees and branches",
+  "Show": "Show",
+  "Some branches could not be deleted": "Some branches could not be deleted",
+  "The branch {0} will be deleted from {1}.": "The branch {0} will be deleted from {1}.",
+  "{0} to pull from {1}": "{0} to pull from {1}",
+  "{0} to push and {1} to pull from {2}": "{0} to push and {1} to pull from {2}",
+  "{0} to push to {1}": "{0} to push to {1}",
+  "Folder missing": "Folder missing",
   "The software catalog could not be loaded. Ask an administrator to check {0}, then try again.": "The software catalog could not be loaded. Ask an administrator to check {0}, then try again.",
   "Edit software catalog": "Edit software catalog",
   "Back to {0}": "Back to {0}",
 
@@ -91,6 +91,16 @@
       <Platform Solution="*|x64" Project="x64" />
     </Project>
   </Folder>
+  <Folder Name="/UniGetUI.Extensions/">
+    <Project Path="UniGetUI.Extensions.GitRepositories/UniGetUI.Extensions.GitRepositories.csproj">
+      <Platform Solution="*|arm64" Project="arm64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+    <Project Path="UniGetUI.Extensions.GitRepositories.Tests/UniGetUI.Extensions.GitRepositories.Tests.csproj">
+      <Platform Solution="*|arm64" Project="arm64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
+  </Folder>
   <Folder Name="/UniGetUI.Interface.Enums/">
     <Project Path="UniGetUI.Interface.Enums/UniGetUI.Interface.Enums.csproj">
       <Platform Solution="*|arm64" Project="arm64" />
 
@@ -0,0 +1,75 @@
+using Avalonia.Controls;
+using UniGetUI.Avalonia.Views;
+using UniGetUI.Avalonia.Views.Pages.SettingsPages;
+using UniGetUI.Core.SettingsEngine;
+using UniGetUI.Core.Tools;
+using UniGetUI.Interface.Enums;
+
+namespace UniGetUI.Avalonia.Infrastructure;
+
+/// <summary>
+/// A built-in, optional part of UniGetUI that goes beyond package management, such as keeping git clones
+/// current. Each is off until turned on from Settings &gt; Extensions, and turns on and off without a restart.
+/// </summary>
+internal sealed class AppExtension
+{
+    /// <summary>Stable identifier, also the page name the CLI and IPC navigate to.</summary>
+    public required string Id { get; init; }
+
+    /// <summary>The English name, translated where it is shown.</summary>
+    public required string Name { get; init; }
+
+    /// <summary>One English sentence on what it does, translated where it is shown.</summary>
+    public required string Description { get; init; }
+
+    public required IconType Icon { get; init; }
+    public required Settings.K EnabledSetting { get; init; }
+    public required PageType Page { get; init; }
+
+    /// <summary>Its page under Settings &gt; Extensions, and how to make one without reflection.</summary>
+    public required Type SettingsPage { get; init; }
+    public required Func<UserControl> CreateSettingsPage { get; init; }
+
+    /// <summary>Starts or stops what it runs in the app, once its setting has changed.</summary>
+    public required Action<bool> ApplyEnabled { get; init; }
+
+    /// <summary>A few words on how it is doing while on, such as "2 behind"; empty when there is nothing to say.</summary>
+    public Func<string> Status { get; init; } = () => "";
+
+    public bool IsEnabled => Settings.Get(EnabledSetting);
+
+    public void SetEnabled(bool enabled)
+    {
+        Settings.Set(EnabledSetting, enabled);
+        ApplyEnabled(enabled);
+    }
+}
+
+internal static class AppExtensions
+{
+    public static readonly AppExtension GitRepositories = new()
+    {
+        Id = "git-repositories",
+        Name = "Git Repositories",
+        Description = "Keep your main git clones up to date and clean up leftover worktrees and branches",
+        Icon = IconType.GitBranch,
+        EnabledSetting = Settings.K.EnableGitRepositories,
+        Page = PageType.GitRepositories,
+        SettingsPage = typeof(GitRepositoriesSettings),
+        CreateSettingsPage = () => new GitRepositoriesSettings(),
+        ApplyEnabled = enabled => MainWindow.Instance?.SetGitRepositoriesEnabled(enabled),
+        Status = () => MainWindow.Instance?.GitRepositories is not { } git
+            ? ""
+            : git.BehindCount > 0
+                ? CoreTools.Translate("{0} behind", git.BehindCount)
+                : git.Repositories.Count switch
+                {
+                    0 => CoreTools.Translate("No clones yet"),
+                    1 => CoreTools.Translate("1 clone"),
+                    int count => CoreTools.Translate("{0} clones", count),
+                },
+    };
+
+    /// <summary>Every extension, in the order Settings lists them.</summary>
+    public static IReadOnlyList<AppExtension> All { get; } = [GitRepositories];
+}
@@ -260,6 +260,7 @@ private static IpcAppInfo GetAppInfo()
                 {
                     "catalog" => window is { SoftwareCatalogEnabled: true },
                     "catalog-editor" => window is { CatalogEditorEnabled: true },
+                    "git-repositories" => window is { GitRepositoriesEnabled: true },
                     _ => true,
                 })
                 .ToArray(),
@@ -305,6 +306,11 @@ private static IpcCommandResult NavigateApp(IpcAppNavigateRequest request)
                     throw new InvalidOperationException("Catalog Editor is disabled. Enable it in Experimental settings and developer options, then restart UniGetUI.");
                 window.Navigate(page == "catalog-editor" ? PageType.CatalogEditor : PageType.Catalog);
                 break;
+            case "git-repositories":
+                if (!window.GitRepositoriesEnabled)
+                    throw new InvalidOperationException("Git Repositories is turned off. Turn it on in Settings, under Extensions.");
+                window.Navigate(PageType.GitRepositories);
+                break;
             case "settings":
                 window.Navigate(PageType.Settings);
                 break;