Examine source code of HSD StudiPlan Select

{
  "manifest_version": 3,
  "name": "HSD StudiPlan Select",
  "browser_specific_settings": {
    "gecko": {
      "id": "hsd-studiplan-select@jaboll",
      "strict_min_version": "58.0"
    }
  },
  "version": "1.0",
  "description": "Automatically select configured plan",
  "permissions": [
    "scripting",
    "activeTab",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://medien.hs-duesseldorf.de/studium/studiengaenge/*"
      ],
      "js": [
        "plan_selector.js"
      ]
    }
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/plan_selector16.png",
      "48": "icons/plan_selector48.png",
      "128": "icons/plan_selector128.png"
    }
  }
}