Examine source code of Mail Attachment Lens

{
  "manifest_version": 2,
  "name": "Mail Attachment Lens",
  "description": "Turn email attachments into a sortable file list. Filter by type, sender, or date. Download files and clean up source emails.",
  "version": "0.1.3",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "identity",
    "storage",
    "https://gmail.googleapis.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "mail-attachment-lens@kshk123.github.io",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "personallyIdentifyingInfo",
          "personalCommunications"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Open Mail Attachment Lens",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  }
}