Examine source code of web screenshot

{
  "name": "web screenshot",
  "description": "Tool to take full screenshot of whole page",
  "version": "1.0.0",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "128": "icon.png"
  }
}