Examine source code of ProUsers

{
  "manifest_version": 2,
  "name": "ProUsers",
  "description": "The ProUsers extension is an extension for users to connect with each other, share data and collaborate.",
  "version": "1.15",
  "icons": {
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "background": {
    "persistent": true,
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.facebook.com/*"
      ],
      "js": [
        "contentscript.js"
      ]
    }
  ],
  "permissions": [
    "storage",
    "cookies",
    "*://app.visualai.xyz/*",
    "http://localhost:3000/*",
    "*://*.facebook.com/*",
    "*://.facebook.com/*"
  ]
}