Examine source code of Behind The Overlay

{
  "name": "Behind The Overlay",
  "author": "Nicolae Namolovan",
  "description": "One click to close any overlay on any website.",
  "version": "0.2.1",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "js/background.js",
      "js/overlay_remover.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "32": "images/courtain_32.png",
      "38": "images/courtain_38.png",
      "64": "images/courtain_64.png"
    },
    "default_title": "❌ Overlay from this page"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+X"
      },
      "description": "❌ Overlay from this page"
    }
  },
  "icons": {
    "128": "images/courtain_128.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "jid1-Y3WfE7td45aWDw@jetpack"
    }
  }
}