Examine source code of Recording icon

{
  "manifest_version": 2,
  "name": "Recording icon",
  "version": "1.0",
  "description": "The recording icon is used to record voice or sound. This icon usually has a microphone – an intuitive and common symbol on mobile devices.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Click me!"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3a0a2489-9ebd-4b89-8220-ef67306dcf1e}"
    }
  }
}