Examine source code of Schulmanager Plus

{
  "manifest_version": 2,
  "name": "Schulmanager Plus",
  "version": "1.2",
  "description": "Dark-Mode und Tweaks für Schulmanager Online",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.schulmanager-online.de/*"
      ],
      "js": [
        "color.js"
      ],
      "css": [
        "color.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "schulmanager_dark_mode@marlon49"
    },
    "data_collection_permissions": {
      "required": [
        "none"
      ],
      "optional": [
        "none"
      ]
    }
  }
}