GB WhatsApp is a modified version of the original WhatsApp app, offering additional features and customization options not found in the official app. It allows users to use two WhatsApp accounts on the same device, customize themes, hide read receipts, and more. However, it is not officially supported by WhatsApp and may come with risks, such as privacy concerns and potential bans from the official app. Users should consider these factors before downloading and using GB WhatsApp.