Examine source code of Lichess Berserker

{
  "manifest_version": 2,
  "name": "Lichess Berserker",
  "version": "1.2resigned1",
  "description": "Lichess berserker",
  "icons": {
    "48": "icons/star-xxl.png"
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "32": "icons/star-empty-38.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.lichess.org/*"
      ],
      "js": [
        "Main.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{7a379491-ab31-4564-8bd0-d487bc3aa038}"
    }
  }
}