Examine source code of Dark Safebooru

{
  "manifest_version": 2,
  "name": "Dark Safebooru",
  "version": "1",
  "description": "Makes Safebooru force dark mode",
  "content_scripts": [
    {
      "matches": [
        "https://safebooru.org/*"
      ],
      "css": [
        "default.css",
        "desktop.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8a7b2a49-f2b6-4061-9932-cd80275b7019}"
    }
  }
}