Examine source code of VoipCenter Extension

{
  "manifest_version": 2,
  "name": "VoipCenter Extension",
  "version": "2.3resigned1",
  "description": "Maakt telefoonnummers op webpagina's aanklikbaar om direct via je IP -of Softphone te kunnen bellen. Zie ook met één klik de status van je collega's, pas je eigen status aan, maak Function Indicators actief of inactief, ...",
  "applications": {
    "gecko": {
      "id": "extension@voipcenter.be"
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "24": "images/icon24.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png",
    "256": "images/icon256.png",
    "512": "images/icon512.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "images/icon16.png",
      "24": "images/icon24.png"
    },
    "default_popup": "popup.html",
    "default_title": "VoipCenter Extension"
  },
  "permissions": [
    "activeTab",
    "notifications",
    "storage",
    "contextMenus",
    "http://pbxonline.be/",
    "https://pbxonline.be/"
  ],
  "background": {
    "scripts": [
      "js/jquery-3.2.1.min.js",
      "js/socket.io.js",
      "js/config.ini.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "css/content.css"
      ],
      "js": [
        "js/jquery-3.2.1.min.js",
        "js/jquery.ba-replacetext.min.js",
        "content.js"
      ]
    }
  ],
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+V",
        "mac": "MacCtrl+Shift+V"
      },
      "description": "Opens popup.html"
    }
  },
  "web_accessible_resources": [
    "images/*.png"
  ]
}