Examine source code of Analog Clock

{
  "manifest_version": 2,
  "name": "Analog Clock",
  "description": "A Analog clock created with html and css",
  "homepage_url": "https://github.com/sriram23",
  "version": "1.0",
  "icons": {
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png"
  },
  "browser_action": {
    "default_popup": "clock/index.html",
    "default_title": "Analog Clock"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c466fdee-45b4-46bf-af6e-2c18a65a2eda}"
    }
  }
}