Examine source code of Borstension

{
  "name": "Borstension",
  "description": "Quick access to Borke in your browser!",
  "version": "1.0",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icon16.jpg",
    "32": "icon32.jpg",
    "48": "icon48.jpg",
    "128": "icon128.jpg"
  },
  "default_icon": {
    "16": "icon16.jpg",
    "32": "icon32.jpg"
  }
}