Examine source code of Download All Files

{
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "version": "1.6.0",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "default_locale": "en",
  "permissions": [
    "activeTab",
    "scripting",
    "downloads",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "firefox@download-all-files.xyz",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "optional_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Download All Files",
    "default_popup": "popup.html"
  }
}