Examine source code of MetaMask

{
  "manifest_version": 2,
  "name": "MetaMask",
  "version": "121.1",
  "description": "MetaMask is the world’s most secure and flexible crypto wallet, trusted by millions of users to buy, sell, and swap digital assets. Manage your portfolio, interact with dapps, and jump into the decentralized web.",
  "browser_action": {
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d7f379f6-b04e-4599-b325-b03297b0b1d3}"
    }
  }
}