Examine source code of Quick Screenshot Collage

{
  "manifest_version": 2,
  "name": "Quick Screenshot Collage",
  "description": "Capture several screenshots of the current tab and merge into a collage (2x2,3x3). Save PNG.",
  "version": "1.0",
  "permissions": [
    "tabs",
    "activeTab",
    "downloads",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Quick Screenshot Collage",
    "default_popup": "popup.html"
  },
  "icons": {
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "quickscreenshotcollage-0bea2289@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}