Examine source code of Gear icon

{
  "manifest_version": 2,
  "name": "Gear icon",
  "version": "1.0",
  "description": "Gear symbol is a mechanical part used to transmit motion and force between shafts, they are present in most machines, from simple to complex.",
  "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": "{ca6fc116-2fde-4450-b0f7-e351512665fc}"
    }
  }
}