Examine source code of Volkker Tech 2FA

{
  "manifest_version": 2,
  "name": "Volkker Tech 2FA",
  "version": "2.0.0",
  "description": "TOTP 2FA code generator by Volkker Tech",
  "author": "Volkker Tech",
  "browser_specific_settings": {
    "gecko": {
      "id": "2fa@volkkertech.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "contextMenus",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "totp.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  }
}