Examine source code of Dark BBC

{
  "name": "BBC Dark",
  "version": "7.1",
  "manifest_version": 3,
  "description": "Used to darken the look of the BBC website.",
  "short_name": "BBC Dark",
  "author": "Deco",
  "icons": {
    "128": "icon3.png",
    "256": "icon2.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.bbc.bg/*",
        "https://www.bbc.click/*",
        "https://www.bbc.co.uk/*",
        "https://www.bbc.cymru/*",
        "https://www.bbc.cz/*",
        "https://www.bbc.digital/*",
        "https://www.bbc.eu/*",
        "https://www.bbc.london/*",
        "https://www.bbc.mobi/*",
        "https://www.bbc.com/*",
        "https://www.bbc.tokyo/*"
      ],
      "css": [
        "code1.css",
        "sports.css",
        "main.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{153b2d6d-206a-43ac-9c53-afb2f4d6ea2d}",
      "strict_min_version": "109.0"
    }
  }
}