Examine source code of WebRTC Blocker

{
  "manifest_version": 2,
  "name": "WebRTC Blocker",
  "description": "Disables WebRTC to prevent IP leak while on VPN.",
  "version": "2.1.1resigned1",
  "browser_action": {
    "browser_style": false,
    "default_icon": "images/48-disabled.png",
    "default_popup": "popup.html",
    "default_title": "Shux! Your IP is visible"
  },
  "icons": {
    "16": "images/32.png",
    "32": "images/32.png",
    "48": "images/48.png",
    "128": "images/128.png"
  },
  "permissions": [
    "privacy",
    "storage",
    "management",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "js/background.js"
    ]
  },
  "applications": {
    "gecko": {
      "strict_min_version": "54.0a1",
      "id": "@webrtc-Blocker"
    }
  }
}