Examine source code of Never Give Up!

{
  "manifest_version": 3,
  "name": "Never Give Up!",
  "description": "Blundered a piece? Lost your queen?\nThis tiny extension turns the resign button into a chill golden reminder: Never give up. Keep fighting. Every mistake is just fuel to come back stronger.\n\nPure CSS vibes – no JavaScript, all heart. ♟️✨\n\nLoving it? Support the dev: https://buymeacoffee.com/realnoname ☕",
  "version": "1.1",
  "icons": {
    "128": "icon.png"
  },
  "action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "never-give-up@realnoname.dev",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.chess.com/*",
        "*://lichess.org/*"
      ],
      "css": [
        "nevergiveup.css"
      ],
      "run_at": "document_end"
    }
  ]
}