@@ -0,0 +1,58 @@
+Index: toolkit/mozapps/extensions/src/nsExtensionManager.js.in
+================================================================================
+--- toolkit/mozapps/extensions/src/nsExtensionManager.js.in
++++ toolkit/mozapps/extensions/src/nsExtensionManager.js.in
+@@ -119,6 +119,7 @@
+
+ const KEY_APP_PROFILE = "app-profile";
+ const KEY_APP_GLOBAL = "app-global";
++const KEY_APP_SYSTEM = "app-system";
+
+ const CATEGORY_INSTALL_LOCATIONS = "extension-install-locations";
+
+@@ -2676,6 +2677,16 @@
+ priority);
+ InstallLocations.put(profileLocation);
+
++ // Register App-System Install Location
++ try {
++ var appSystemExtensions = getDirNoCreate("DrvD", ["usr","lib","browser-extensions","firefox"]);
++ var priority = nsIInstallLocation.PRIORITY_APP_PROFILE - 1;
++ var systemLocation = new DirectoryInstallLocation(KEY_APP_SYSTEM,
++ appSystemExtensions, true,
++ priority);
++ InstallLocations.put(systemLocation);
++ } catch (e) {}
++
+ #ifdef XP_WIN
+ // Register HKEY_LOCAL_MACHINE Install Location
+ InstallLocations.put(
+@@ -3852,7 +3863,7 @@
+
+ // Prepare themes for installation
+ // Only enumerate directories in the app-profile and app-global locations.
+- var locations = [KEY_APP_PROFILE, KEY_APP_GLOBAL];
++ var locations = [KEY_APP_PROFILE, KEY_APP_GLOBAL, KEY_APP_SYSTEM];
+ for (var i = 0; i < locations.length; ++i) {
+ var location = InstallLocations.get(locations[i]);
+ if (!location.canAccess)
+@@ -3918,7 +3929,8 @@
+ var items = PendingOperations.getOperations(OP_NEEDS_INSTALL);
+ for (i = items.length - 1; i >= 0; --i) {
+ if (items[i].locationKey == KEY_APP_PROFILE ||
+- items[i].locationKey == KEY_APP_GLOBAL)
++ items[i].locationKey == KEY_APP_GLOBAL ||
++ items[i].locationKey == KEY_APP_SYSTEM)
+ itemsToCheck.push(items[i].id);
+ }
+ this._finishOperations();
+@@ -4903,7 +4915,8 @@
+ }
+ }
+ else if (installLocation.name == KEY_APP_PROFILE ||
+- installLocation.name == KEY_APP_GLOBAL) {
++ installLocation.name == KEY_APP_GLOBAL ||
++ installLocation.name == KEY_APP_SYSTEM) {
+ // Check for a pointer file and remove it if it exists
+ var pointerFile = installLocation.location.clone();
+ pointerFile.append(id);
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