Examine source code of Freelancer Manager

{
  "name": "Freelancer Manager",
  "description": "Submit bids rapidly, Manage bids on Freelancing websites...",
  "version": "1.1.0",
  "manifest_version": 2,
  "icons": {
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "contents/styles.css"
      ],
      "js": [
        "browser-polyfill.js",
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "freelancermanager@workoment.com"
    }
  },
  "browser_action": {
    "default_title": "Freelancer Manager",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js"
    ]
  },
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAow+iezLmkltw5nQoC6yCq7RNqNDXabeazS9DpbD/uIVMJ5dkOPgpYvkrffMg26rPU1eyUmHu8KrdcbejdjKMhShF9AgfQsIBveqDn2vQAn0eRKNYbYblvR8M3Uh8Ifx2mtS2WfU6iiAFuA5JritMqCaSi0ybjzA69oytE4HP9tX+nuiifJdW3xzx7ARuPglFS941FpAOQ7+BdXVDg88KeBa52U9r3edpePKRP/YGNn+QC3xjGuxJ5ri43UDzhQmw9BVkq5A6ar25klRIMKggnfcqbkK9KkeD5hkePQHOvntGfFH51/sUVbpdH2zSNsPF5QvmPgo5mOIADxAc+HDl9QIDAQAB",
  "id": "bcajabaonhinjakmjmemlgolhlcgncje",
  "optional_permissions": [
    "*://*/"
  ],
  "options_ui": {
    "chrome_style": true,
    "open_in_tab": true,
    "page": "settings/settings.html"
  },
  "permissions": [
    "contextMenus",
    "activeTab",
    "tabs",
    "storage",
    "nativeMessaging",
    "*://*.freelancer.com/*",
    "*://freelancer.com/*",
    "*://*.upwork.com/*"
  ],
  "content_security_policy": "script-src 'self' https://*.atatus.com https://www.google-analytics.com; object-src 'self'"
}