Examine source code of Schulmanager Dark-Mode

{
  "manifest_version": 2,
  "name": "Schulmanager Dark-Mode",
  "version": "1.1",
  "description": "Adds a Dark Mode to the website 'Schulmanager Online'",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.schulmanager-online.de/*"
      ],
      "js": [
        "color.js"
      ],
      "css": [
        "color.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "schulmanager_dark_mode@marlon49"
    }
  }
}