Examine source code of HTML Download

{
  "manifest_version": 2,
  "name": "HTML Download",
  "version": "1.1",
  "description": "Download HTML content to .html file",
  "homepage_url": "https://github.com/juanpabloch/extension-html-download",
  "icons": {
    "48": "icons/html-color-100.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/html-color-100.png",
    "default_title": "HTML Download",
    "default_popup": "popup/choose_beast.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6945cfc6-4f9f-4e6b-a9a0-86607ddec160}"
    }
  }
}