Examine source code of Klubkasse

{
  "manifest_version": 2,
  "name": "klubkasse.de",
  "version": "0.7.12",
  "description": "Die App mit der Du für Deinen Verein shoppen kannst.",
  "homepage_url": "https://www.klubkasse.de",
  "options_ui": {
    "page": "/index.html?page=options"
  },
  "icons": {
    "16": "/img/icons/login.png",
    "24": "/img/icons/login.png",
    "32": "/img/icons/login.png",
    "48": "/img/icons/login.png",
    "64": "/img/icons/login.png",
    "96": "/img/icons/login.png",
    "128": "/img/icons/login.png",
    "256": "/img/icons/login.png"
  },
  "web_accessible_resources": [
    "img/*"
  ],
  "background": {
    "page": "/index.html?page=background"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "/js/content-script.js"
      ]
    }
  ],
  "browser_action": {
    "default_title": "Klubkasse.de",
    "default_icon": {
      "16": "/img/icons/login.png",
      "24": "/img/icons/login.png",
      "32": "/img/icons/login.png",
      "48": "/img/icons/login.png",
      "64": "/img/icons/login.png",
      "96": "/img/icons/login.png",
      "128": "/img/icons/login.png",
      "256": "/img/icons/login.png"
    },
    "default_popup": "/index.html"
  },
  "permissions": [
    "storage",
    "tabs",
    "notifications",
    "webRequest",
    "webRequestBlocking",
    "http://*/*",
    "https://*/*"
  ],
  "applications": {
    "gecko": {
      "id": "firefox-extension@klubkasse.de"
    }
  }
}