Examine source code of Lichess LIFBA Theme

{
  "manifest_version": 2,
  "name": "Lichess LIFBA Theme",
  "version": "0.1",
  "description": "Fancy board animation theme for Lichess",
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://lichess.org/*"
      ],
      "css": [
        "lifba.css"
      ],
      "js": [
        "lifba.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "lifba@sarchreato.org"
    }
  }
}