diff --git a/extension/firefox/manifest.json b/extension/firefox/manifest.json
index d4292d18..56a60889 100644
--- a/extension/firefox/manifest.json
+++ b/extension/firefox/manifest.json
@@ -1,28 +1,22 @@
 {
   "version": "3.1.10",
   "name": "Redux DevTools",
-  "manifest_version": 2,
+  "manifest_version": 3,
   "description": "Redux Developer Tools for debugging application state changes.",
   "homepage_url": "https://github.com/reduxjs/redux-devtools",
-  "applications": {
+  "browser_specific_settings": {
     "gecko": {
       "id": "extension@redux.devtools"
     }
   },
-  "page_action": {
+  "action": {
     "default_icon": "img/logo/38x38.png",
     "default_title": "Redux DevTools",
-    "default_popup": "window.html#popup"
+    "default_popup": "devpanel.html#popup"
   },
   "commands": {
-    "devtools-left": {
-      "description": "DevTools window to left"
-    },
-    "devtools-right": {
-      "description": "DevTools window to right"
-    },
-    "devtools-bottom": {
-      "description": "DevTools window to bottom"
+    "devtools-window": {
+      "description": "DevTools window"
     },
     "devtools-remote": {
       "description": "Remote DevTools"
@@ -42,21 +36,22 @@
   "content_scripts": [
     {
       "matches": ["<all_urls>"],
-      "js": ["content.bundle.js", "pagewrap.bundle.js"],
+      "js": ["content.bundle.js"],
       "run_at": "document_start",
       "all_frames": true
+    },
+    {
+      "matches": ["<all_urls>"],
+      "js": ["page.bundle.js"],
+      "run_at": "document_start",
+      "all_frames": true,
+      "world": "MAIN"
     }
   ],
   "devtools_page": "devtools.html",
-  "web_accessible_resources": ["page.bundle.js"],
-  "permissions": [
-    "notifications",
-    "contextMenus",
-    "tabs",
-    "storage",
-    "file:///*",
-    "http://*/*",
-    "https://*/*"
-  ],
-  "content_security_policy": "script-src 'self'; object-src 'self'; img-src 'self' data:;"
+  "permissions": ["notifications", "contextMenus", "tabs", "storage"],
+  "host_permissions": ["file:///*", "http://*/*", "https://*/*"],
+  "content_security_policy": {
+    "extension_pages": "script-src 'self'; object-src 'self'; img-src 'self' data:;"
+  }
 }