Examine source code of Desmos: Dark Mode

{
  "name": "Desmos: Dark Mode",
  "version": "0.1.3",
  "manifest_version": 2,
  "description": "Dark Mode for Desmos",
  "content_scripts": [
    {
      "matches": [
        "https://*.desmos.com/calculator"
      ],
      "css": [
        "dark.css"
      ]
    }
  ],
  "icons": {
    "128": "iconhlf.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6e3f5ebd-5daf-46d4-8f81-6977b6a67599}"
    }
  }
}