stylessh · stylessh · Apr 10, 2026 · Apr 10, 2026
diff --git a/extensions/diffkit-redirect/README.md b/extensions/diffkit-redirect/README.md
@@ -0,0 +1,81 @@
+# DiffKit Extension
+
+Standalone browser extension for redirecting only selected GitHub URLs to DiffKit.
+
+## What it does
+
+- Redirects matching GitHub URLs at page start
+- Lets you keep the extension globally enabled or disabled
+- Shows one toggle per redirect rule in the popup
+- Uses a configurable list of rules instead of redirecting every GitHub page
+- Supports both exact URL redirects and regex-based route schemas
+- Supports custom route remaps like GitHub PR changes pages to DiffKit review pages
+
+## Default rule
+
+The extension ships with these enabled rules:
+
+- `https://github.com/`
+- `https://diff-kit.com/`
+- `https://github.com/pulls/*`
+- `https://diff-kit.com/pulls`
+- `https://github.com/issues/*`
+- `https://diff-kit.com/issues`
+- `https://github.com/:owner/:repo/pull/:number`
+- `https://diff-kit.com/:owner/:repo/pull/:number`
+- `https://github.com/:owner/:repo/pull/:number/changes`
+- `https://diff-kit.com/:owner/:repo/review/:number`
+- `https://github.com/:owner/:repo/issues/:number`
+- `https://diff-kit.com/:owner/:repo/issues/:number`
+
+## Rule format
+
+```json
+[
+  {
+    "id": "github-pull-details",
+    "label": "Pull request details",
+    "description": "Redirect GitHub pull request detail pages to DiffKit.",
+    "enabled": true,
+    "match": {
+      "urlRegex": "^https://github\\.com/([^/?#]+)/([^/?#]+)/pull/(\\d+)/?$",
+      "excludeUrlRegexes": []
+    },
+    "redirect": {
+      "replacement": "https://diff-kit.com/$1/$2/pull/$3"
+    }
+  }
+]
+```
+
+For an exact URL redirect, use:
+
+```json
+{
+    "id": "one-off",
+    "label": "Specific PR page",
+    "description": "Single URL redirect",
+    "enabled": true,
+    "match": {
+      "exactUrl": "https://github.com/org/repo/pull/123"
+  },
+  "redirect": {
+    "url": "https://diff-kit.com/org/repo/pull/123"
+  }
+}
+```
+
+## Install locally
+
+1. Open `chrome://extensions`
+2. Enable Developer mode
+3. Click Load unpacked
+4. Select `extensions/diffkit-redirect`
+
+## Scope
+
+This version is intentionally limited to `github.com` in `manifest.json`. If you later want redirects from other source hosts, add those hosts to the extension matches and permissions.
+
+## Popup behavior
+
+The popup keeps all default rules enabled unless you turn specific ones off. Use the master switch to pause all redirects without losing your per-rule selections.
diff --git a/extensions/diffkit-redirect/content.js b/extensions/diffkit-redirect/content.js
@@ -0,0 +1,22 @@
+(async function runRedirect() {
+  const shared = globalThis.DiffKitRedirect;
+  if (!shared) {
+    return;
+  }
+
+  try {
+    const config = await shared.getConfig();
+    if (!config.enabled) {
+      return;
+    }
+
+    const redirect = shared.findRedirect(window.location.href, config.rules);
+    if (!redirect) {
+      return;
+    }
+
+    window.location.replace(redirect.targetUrl);
+  } catch (error) {
+    console.error("DiffKit: failed to evaluate redirect.", error);
+  }
+})();
diff --git a/extensions/diffkit-redirect/icons/icon-128.png b/extensions/diffkit-redirect/icons/icon-128.png
diff --git a/extensions/diffkit-redirect/icons/icon-16.png b/extensions/diffkit-redirect/icons/icon-16.png
diff --git a/extensions/diffkit-redirect/icons/icon-32.png b/extensions/diffkit-redirect/icons/icon-32.png
diff --git a/extensions/diffkit-redirect/icons/icon-48.png b/extensions/diffkit-redirect/icons/icon-48.png
diff --git a/extensions/diffkit-redirect/icons/logo.svg b/extensions/diffkit-redirect/icons/logo.svg
diff --git a/extensions/diffkit-redirect/manifest.json b/extensions/diffkit-redirect/manifest.json
@@ -0,0 +1,30 @@
+{
+  "manifest_version": 3,
+  "name": "DiffKit",
+  "version": "0.1.0",
+  "description": "Redirect selected GitHub URLs to matching DiffKit routes.",
+  "icons": {
+    "16": "icons/icon-16.png",
+    "32": "icons/icon-32.png",
+    "48": "icons/icon-48.png",
+    "128": "icons/icon-128.png"
+  },
+  "permissions": ["storage"],
+  "host_permissions": ["https://github.com/*"],
+  "action": {
+    "default_title": "DiffKit",
+    "default_popup": "popup.html",
+    "default_icon": {
+      "16": "icons/icon-16.png",
+      "32": "icons/icon-32.png"
+    }
+  },
+  "options_page": "options.html",
+  "content_scripts": [
+    {
+      "matches": ["https://github.com/*"],
+      "js": ["shared.js", "content.js"],
+      "run_at": "document_start"
+    }
+  ]
+}
diff --git a/extensions/diffkit-redirect/options.html b/extensions/diffkit-redirect/options.html
@@ -0,0 +1,74 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title>DiffKit Options</title>
+    <link rel="stylesheet" href="styles.css">
+  </head>
+  <body>
+    <main class="options-layout">
+      <section class="options-panel">
+        <div class="options-header">
+          <div>
+            <p class="eyebrow">DiffKit</p>
+            <h1>Redirect rules</h1>
+          </div>
+
+          <label class="toggle-row">
+            <span>Enabled</span>
+            <input id="enabled-toggle" type="checkbox">
+          </label>
+        </div>
+
+        <p class="muted">
+          Add only the GitHub routes DiffKit currently supports. A rule can
+          match a single exact URL or a regex pattern over the full URL.
+        </p>
+
+        <textarea
+          id="rules-editor"
+          class="rules-editor"
+          spellcheck="false"
+        ></textarea>
+
+        <div class="panel-actions">
+          <button id="save-button" type="button">Save rules</button>
+          <button id="reset-button" type="button" class="secondary">
+            Reset defaults
+          </button>
+        </div>
+
+        <p id="save-status" class="status-copy"></p>
+      </section>
+
+      <aside class="help-panel">
+        <h2>Rule shape</h2>
+        <pre class="code-block">{
+  "id": "github-pull-details",
+  "label": "Pull request details",
+  "description": "Redirect GitHub pull request detail pages to DiffKit.",
+  "enabled": true,
+  "match": {
+    "urlRegex": "^https://github\\.com/([^/?#]+)/([^/?#]+)/pull/(\\d+)/?$",
+    "excludeUrlRegexes": []
+  },
+  "redirect": {
+    "replacement": "https://diff-kit.com/$1/$2/pull/$3"
+  }
+}</pre>
+
+        <p class="muted">
+          <code>label</code>
+          is optional but recommended so the popup can show a clean toggle name.
+          For one-off routes, use <code>match.exactUrl</code> and
+          <code>redirect.url</code>
+          instead.
+        </p>
+      </aside>
+    </main>
+
+    <script src="shared.js"></script>
+    <script src="options.js"></script>
+  </body>
+</html>
diff --git a/extensions/diffkit-redirect/options.js b/extensions/diffkit-redirect/options.js
@@ -0,0 +1,58 @@
+(async function initOptions() {
+  const shared = globalThis.DiffKitRedirect;
+  const enabledToggle = document.getElementById("enabled-toggle");
+  const rulesEditor = document.getElementById("rules-editor");
+  const saveButton = document.getElementById("save-button");
+  const resetButton = document.getElementById("reset-button");
+  const saveStatus = document.getElementById("save-status");
+
+  function setStatus(message, tone) {
+    saveStatus.textContent = message;
+    saveStatus.dataset.tone = tone || "";
+  }
+
+  async function loadConfig() {
+    const config = await shared.getConfig();
+    enabledToggle.checked = config.enabled;
+    rulesEditor.value = JSON.stringify(config.rules, null, 2);
+
+    if (config.validationErrors.length > 0) {
+      setStatus(config.validationErrors.join(" "), "error");
+      return;
+    }
+
+    setStatus("", "");
+  }
+
+  async function saveConfig() {
+    let parsedRules;
+    try {
+      parsedRules = JSON.parse(rulesEditor.value);
+    } catch {
+      setStatus("Rules must be valid JSON.", "error");
+      return;
+    }
+
+    const result = await shared.saveConfig({
+      enabled: enabledToggle.checked,
+      rules: parsedRules,
+    });
+
+    if (!result.ok) {
+      setStatus(result.errors.join(" "), "error");
+      return;
+    }
+
+    setStatus("Rules saved.", "success");
+    await loadConfig();
+  }
+
+  saveButton.addEventListener("click", saveConfig);
+
+  resetButton.addEventListener("click", () => {
+    rulesEditor.value = JSON.stringify(shared.getDefaultRules(), null, 2);
+    setStatus("Defaults restored in the editor. Save to apply them.", "");
+  });
+
+  await loadConfig();
+})();
diff --git a/extensions/diffkit-redirect/popup.html b/extensions/diffkit-redirect/popup.html
@@ -0,0 +1,41 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title>DiffKit</title>
+    <link rel="stylesheet" href="styles.css">
+  </head>
+  <body class="popup-body">
+    <main class="popup-shell">
+      <section class="popup-card">
+        <div class="brand-row">
+          <div class="brand-lockup">
+            <img class="brand-logo" src="icons/logo.svg" alt="DiffKit">
+            <div>
+              <p class="eyebrow">DiffKit</p>
+              <h1>GitHub redirects</h1>
+            </div>
+          </div>
+          <label class="switch" aria-label="Toggle redirects">
+            <input id="enabled-toggle" type="checkbox">
+            <span class="switch-track"></span>
+          </label>
+        </div>
+
+        <p class="lede">
+          Choose which GitHub routes should jump into DiffKit automatically.
+        </p>
+
+        <div id="rule-list" class="rule-list" role="list"></div>
+
+        <div class="status-row">
+          <p id="status-copy" class="status-copy">Loading…</p>
+        </div>
+      </section>
+    </main>
+
+    <script src="shared.js"></script>
+    <script src="popup.js"></script>
+  </body>
+</html>