Examine source code of A1 Full Page Capture

{
  "manifest_version": 3,
  "name": "A1 Full Page Capture",
  "short_name": "A1 Capture",
  "version": "0.1.0",
  "description": "Capture the visible-width full page from the active tab, stitch it locally, and save PNG or JPEG files after user action.",
  "homepage_url": "https://a1local.com.au/extensions/full-page-capture/",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "action": {
    "default_title": "A1 Full Page Capture",
    "default_popup": "popup.html"
  },
  "options_page": "options.html",
  "permissions": [
    "activeTab",
    "scripting",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "full-page-capture@a1local.com.au",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "strict_min_version": "142.0"
    }
  }
}