Examine source code of Gmail Link Fixer

{
  "name": "Gmail Link Fixer",
  "description": "Changes Gmail specific links to standard mailto: links.",
  "version": "1.2.1",
  "manifest_version": 2,
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*.google.com/*"
  ],
  "background": {
    "scripts": [
      "background.min.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "images/email-button-16.png",
    "default_title": "Gmail Link Fixer is on"
  },
  "icons": {
    "16": "images/email-button-16.png",
    "32": "images/email-button-32.png",
    "48": "images/email-button-48.png",
    "64": "images/email-button-64.png",
    "128": "images/email-button-128.png"
  }
}