--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1631,22 +1631,22 @@ pref("browser.crashReports.unsubmittedCh
 // crash report notification across different days and shutdown
 // without a user choice before we suppress the notification for
 // some number of days.
 pref("browser.crashReports.unsubmittedCheck.chancesUntilSuppress", 4);
 pref("browser.crashReports.unsubmittedCheck.autoSubmit", false);
 
 // Preferences for the form autofill system extension
 #ifdef NIGHTLY_BUILD
-pref("browser.formautofill.experimental", true);
+pref("extensions.formautofill.experimental", true);
 #else
-pref("browser.formautofill.experimental", false);
+pref("extensions.formautofill.experimental", false);
 #endif
 pref("extensions.formautofill.addresses.enabled", true);
-pref("browser.formautofill.loglevel", "Warn");
+pref("extensions.formautofill.loglevel", "Warn");
 
 // Whether or not to restore a session with lazy-browser tabs.
 pref("browser.sessionstore.restore_tabs_lazily", true);
 
 // Enable safebrowsing v4 tables (suffixed by "-proto") update.
 #ifdef NIGHTLY_BUILD
 pref("urlclassifier.malwareTable", "goog-malware-shavar,goog-unwanted-shavar,goog-malware-proto,goog-unwanted-proto,test-malware-simple,test-unwanted-simple");
 pref("urlclassifier.phishTable", "goog-phish-shavar,goog-phish-proto,test-phish-simple");

--- a/browser/extensions/formautofill/FormAutofillUtils.jsm
+++ b/browser/extensions/formautofill/FormAutofillUtils.jsm
@@ -10,17 +10,17 @@ const {classes: Cc, interfaces: Ci, util
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 this.FormAutofillUtils = {
   defineLazyLogGetter(scope, logPrefix) {
     XPCOMUtils.defineLazyGetter(scope, "log", () => {
       let ConsoleAPI = Cu.import("resource://gre/modules/Console.jsm", {}).ConsoleAPI;
       return new ConsoleAPI({
-        maxLogLevelPref: "browser.formautofill.loglevel",
+        maxLogLevelPref: "extensions.formautofill.loglevel",
         prefix: logPrefix,
       });
     });
   },
 
   findLabelElements(element) {
     let document = element.ownerDocument;
     let labels = [];

--- a/browser/extensions/formautofill/bootstrap.js
+++ b/browser/extensions/formautofill/bootstrap.js
@@ -36,17 +36,17 @@ let windowListener = {
 
     domWindow.addEventListener("load", function onWindowLoaded() {
       insertStyleSheet(domWindow, STYLESHEET_URI);
     }, {once: true});
   },
 };
 
 function startup() {
-  if (!Services.prefs.getBoolPref("browser.formautofill.experimental")) {
+  if (!Services.prefs.getBoolPref("extensions.formautofill.experimental")) {
     return;
   }
 
   let parent = new FormAutofillParent();
   let enumerator = Services.wm.getEnumerator("navigator:browser");
   // Load stylesheet to already opened windows
   while (enumerator.hasMoreElements()) {
     let win = enumerator.getNext();

--- a/browser/extensions/formautofill/test/unit/head.js
+++ b/browser/extensions/formautofill/test/unit/head.js
@@ -114,15 +114,15 @@ function runHeuristicsTest(patterns, fix
           Assert.deepEqual(field, expectedField);
         });
       });
     });
   });
 }
 
 add_task(function* head_initialize() {
-  Services.prefs.setBoolPref("browser.formautofill.experimental", true);
+  Services.prefs.setBoolPref("extensions.formautofill.experimental", true);
 
   // Clean up after every test.
   do_register_cleanup(function head_cleanup() {
-    Services.prefs.clearUserPref("browser.formautofill.experimental");
+    Services.prefs.clearUserPref("extensions.formautofill.experimental");
   });
 });

--- a/testing/profiles/prefs_general.js
+++ b/testing/profiles/prefs_general.js
@@ -358,17 +358,17 @@ user_pref("media.libavcodec.allow-obsole
 
 user_pref("media.openUnsupportedTypeWithExternalApp", false);
 
 // Disable password capture, so that mochitests that include forms aren't
 // influenced by the presence of the persistent doorhanger notification.
 user_pref("signon.rememberSignons", false);
 
 // Enable form autofill feature testing.
-user_pref("browser.formautofill.experimental", true);
+user_pref("extensions.formautofill.experimental", true);
 
 // Disable all recommended Marionette preferences for Gecko tests.
 // The prefs recommended by Marionette are typically geared towards
 // consumer automation; not vendor testing.
 user_pref("marionette.prefs.recommended", false);
 
 // Disable Screenshots by default for now
 user_pref("extensions.screenshots.system-disabled", true);