Examine source code of Rapla++

{
  "manifest_version": 2,
  "name": "raplaPlusPlus",
  "version": "1.2",
  "description": "Makes for a more fancy version of RaPla.",
  "icons": {
    "128": "logo.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://rapla.dhbw-karlsruhe.de/rapla?page=calendar*"
      ],
      "run_at": "document_start",
      "css": [
        "main.css"
      ],
      "js": [
        "injected.js"
      ]
    }
  ]
}