Examine source code of Monitor Web Pages

{
  "manifest_version": 2,
  "version": "1.0.5resigned1",
  "name": "Monitor Web Pages",
  "description": "Monitor your web pages integrity and availability by tracking content-length and modified-date",
  "author": "Moris Papasmadov",
  "homepage_url": "https://addons.mozilla.org/en-US/firefox/user/morisdov/",
  "applications": {
    "gecko": {
      "id": "morisdov@monitorwebpages",
      "strict_min_version": "45.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "*://*/*",
    "webRequest",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon/icon-64.png"
  },
  "icons": {
    "16": "icon/icon-16.png",
    "32": "icon/icon-32.png",
    "48": "icon/icon-48.png",
    "64": "icon/icon-64.png"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  }
}