Examine source code of Undo Closed Tabs Menu

{
  "manifest_version": 2,
  "name": "Undo Closed Tabs Menu",
  "version": "2.1resigned1",
  "description": "Shows menu of closed tabs when right clicking on tabs.",
  "homepage_url": "https://github.com/joshuacant/",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "webNavigation",
    "tabs",
    "sessions",
    "menus",
    "storage"
  ],
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "tst-closed_tabs_menu@dontpokebadgers.com",
      "strict_min_version": "57.0a1"
    }
  }
}