Examine source code of Sleep mode icon

{
  "manifest_version": 2,
  "name": "Sleep mode icon",
  "version": "1.0",
  "description": "The sleep mode icon often appears on computers, laptops, phones, televisions, remote controls... to indicate a state of temporary inactivity but still maintains low power levels, helping to save battery without completely turning off the device.",
  "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": "{5fa53b2c-0027-40e2-b21b-683a29f20985}"
    }
  }
}