make about: protocols spoofed to chrome:// protocols and add the chrome dino game

Profile Folder/chrome/JS/dino.uc.js

@@ -0,0 +1,4 @@
+// ==UserScript==
+// @name dino manifest loader
+// @manifest dino
+// ==/UserScript==

Profile Folder/chrome/JS/userChrome.uc.js

@@ -0,0 +1,61 @@
+window.addEventListener("load", function() {
+  const chromeRedirects = {
+    "chrome://settings": "about:preferences",
+    "chrome://extensions": "about:addons",
+    "chrome://history": "about:history",
+    "chrome://downloads": "about:downloads",
+    "chrome://bookmarks": "about:bookmarks",
+  };
+  const chromeDirect = {
+    "chrome://dino": "chrome://dino/content/dino.html",
+  };
+  const reverseRedirects = {};
+  for (let [chrome, about] of Object.entries(chromeRedirects)) {
+    reverseRedirects[about] = chrome;
+  }
+  let lastTypedChrome = null;
+  function spoofURL(url) {
+    if (lastTypedChrome) {
+      gURLBar.value = lastTypedChrome;
+      lastTypedChrome = null;
+      return;
+    }
+    if (url.startsWith("about:") && !url.startsWith("about:newtab") && !url.startsWith("about:blank") && !url.startsWith("about:home")) {
+      gURLBar.value = reverseRedirects[url] || url.replace("about:", "chrome://");
+    }
+  }
+  setTimeout(() => spoofURL(gBrowser.selectedBrowser.currentURI.spec), 500);
+  gBrowser.addTabsProgressListener({
+    onLocationChange(browser, progress, request, location) {
+      if (browser === gBrowser.selectedBrowser) {
+        spoofURL(location.spec);
+      }
+    }
+  });
+  gBrowser.tabContainer.addEventListener("TabSelect", function() {
+    setTimeout(() => spoofURL(gBrowser.selectedBrowser.currentURI.spec), 500);
+  });
+  gURLBar.addEventListener("keydown", function(e) {
+    if (e.key === "Enter") {
+      let val = gURLBar.value.trim();
+      if (val.startsWith("chrome://")) {
+        e.preventDefault();
+        e.stopPropagation();
+        gURLBar.view.close();
+        if (chromeDirect[val]) {
+          lastTypedChrome = val;
+          gBrowser.loadURI(Services.io.newURI(chromeDirect[val]), {
+            triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal()
+          });
+        } else {
+          let real = chromeRedirects[val] || val.replace("chrome://", "about:");
+          lastTypedChrome = val;
+          gBrowser.loadURI(Services.io.newURI(real), {
+            triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal()
+          });
+        }
+        gBrowser.selectedBrowser.focus();
+      }
+    }
+  }, true);
+});