Examine source code of EFM League Assistant

{
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "efm-league-assistant@h-martini.de",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "name": "EFM League Assistant",
  "description": "Optimization of the EFM league interface and aggregation of key data for a smarter, more efficient overview.",
  "version": "0.1.2",
  "permissions": [
    "clipboardWrite"
  ],
  "host_permissions": [
    "https://api.efmleague.de/*"
  ],
  "background": {
    "service_worker": "assets/background.js",
    "scripts": [
      "assets/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.efmleague.de/*"
      ],
      "js": [
        "assets/content.js"
      ],
      "css": [
        "assets/content.css"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "assets/*"
      ],
      "matches": [
        "https://www.efmleague.de/*"
      ]
    }
  ]
}