Examine source code of Screenshot Verifier

{
  "manifest_version": 2,
  "name": "Screenshot Verifier",
  "version": "1.0",
  "description": "Verifies webpage screenshots and shows badge.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Verify Page"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{388e1452-5719-4d00-ba70-525477271aea}"
    }
  }
}