Examine source code of FLApp

{
  "manifest_version": 2,
  "name": "FLApp",
  "description": "Wtyczka do telefonu FiveLife.pl",
  "version": "1.8",
  "icons": {
    "16": "images/16.png",
    "48": "images/48.png",
    "128": "images/128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/16.png",
      "48": "images/48.png",
      "128": "images/128.png"
    }
  },
  "permissions": [
    "*://*.robopryczi.top/*",
    "*://telserv.fivelife.pl/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://tel.fivelife.pl/*"
      ],
      "js": [
        "tel.js"
      ],
      "css": [
        "sources/style.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "sounds/ding.mp3",
    "sounds/radar.mp3",
    "sounds/turn.mp3",
    "images/128.png",
    "images/wysuwakBG.png",
    "sounds/sadzic.mp3",
    "images/spizganySmerf.png",
    "images/ricer.png",
    "sounds/tokyo.mp3",
    "sources/html/wysuwak.html",
    "sources/html/numer.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f7947f0c-f578-460c-a393-7997a5f747f2}"
    }
  }
}