Examine source code of Proxy Certificate Check

{
  "manifest_version": 2,
  "name": "Proxy Certificate Check",
  "version": "1.0",
  "description": "Shows Proxy Certificate Status",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "tabs",
    "webNavigation"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "icons/normal-32.png",
    "default_title": "Checking connection..."
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5c332efd-cf8f-4a43-bdb1-3821a86ca044}"
    }
  }
}