Examine source code of Page Capturer

{
  "manifest_version": 2,
  "name": "Page Capture",
  "version": "1.4.4",
  "description": "Take a screenshot of a whole web page from top to bottom in one click. Automatically scrolls and joins the page into one image, supports retina displays, and exports to PNG or JPEG.",
  "icons": {
    "32": "images/icon-32.png",
    "48": "images/icon-48.png",
    "64": "images/icon-64.png",
    "96": "images/icon-96.png",
    "128": "images/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b7c0669b-ccf6-4d24-8ee7-0d2c218f18e9}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
    "default_title": "Page Capture",
    "default_popup": "app/popup.html",
    "default_icon": {
      "32": "images/icon-32.png",
      "48": "images/icon-48.png",
      "64": "images/icon-64.png"
    }
  }
}