Examine source code of Check4Change

{
  "manifest_version": 2,
  "name": "Check4Change",
  "version": "2.4",
  "description": "Periodically reloads a webpage and alert for specific changes",
  "homepage_url": "https://www.check4change.com",
  "permissions": [
    "activeTab",
    "contextMenus",
    "tabs",
    "webNavigation",
    "<all_urls>",
    "notifications",
    "storage",
    "cookies",
    "webRequest",
    "webRequestBlocking"
  ],
  "applications": {
    "gecko": {
      "id": "check4change-owner@mozdev.org",
      "strict_min_version": "58.0"
    }
  },
  "icons": {
    "16": "icons/c4c.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/c4c.png"
    },
    "default_title": "Check4Change",
    "browser_style": true
  },
  "background": {
    "page": "background.html"
  },
  "web_accessible_resources": [
    "icons/c4c.ico",
    "icons/c4c_1.ico",
    "icons/c4c_2.ico",
    "icons/c4c_3.ico",
    "icons/c4c_4.ico",
    "icons/c4c_5.ico",
    "icons/c4c_6.ico",
    "icons/c4c_7.ico",
    "icons/c4c_8.ico",
    "icons/c4c_9.ico",
    "pages/overlay.html",
    "pages/tutorial.html",
    "pages/settingsDialog.html"
  ]
}