Examine source code of Oona

{
  "manifest_version": 2,
  "name": "Oona",
  "description": "Oona by Vostel",
  "version": "1.2.8",
  "author": "Vostel",
  "browser_action": {
    "default_icon": {
      "16": "images/icon-16.png",
      "32": "images/icon-32.png"
    },
    "default_title": "Oona by Vostel",
    "default_popup": "popup.html"
  },
  "permissions": [
    "*://*.vostel.co.uk/",
    "https://websockets.stan.vostel.co.uk/api/broadcasting/auth",
    "https://api.stan.vostel.co.uk/click-to-call",
    "https://api.stan.vostel.co.uk/ext-login",
    "storage",
    "unlimitedStorage",
    "notifications",
    "contextMenus",
    "cookies",
    "scripting",
    "management",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "css": [
        "css/style.css",
        "css/dialer.css"
      ],
      "js": [
        "js/jquery-3.5.1.min.js",
        "js/jquery.timeago.js",
        "js/button-actions.js",
        "js/sweetalert2.all.min.js",
        "stan.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "images/*",
    "fonts/*"
  ],
  "icons": {
    "16": "images/icon-16.png",
    "32": "images/icon-32.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7fec5928-bf00-4fed-831d-2962ae165e69}"
    }
  }
}