Examine source code of Lichess Puzzle Timer

{
  "manifest_version": 3,
  "name": "Lichess Puzzle Timer",
  "version": "1.7",
  "description": "Adds a timer to the lichess.org puzzle trainer to help you think through variations before making a move.",
  "icons": {
    "48": "logo-48x48.png",
    "128": "logo-128x128.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "lichess-puzzle-timer@catswhisker.xyz",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.lichess.org/training*"
      ],
      "js": [
        "lctimer.js"
      ],
      "css": [
        "lctimer.css"
      ]
    }
  ]
}