Duplicate Tab Shortcut is a free Chrome add-on developed by Stefan. As the name suggests, this add-on allows users to quickly duplicate their current tab with a simple keyboard shortcut. For Windows users, the shortcut is Alt+Shift+D, while Mac users can use Option+Shift+D.

In addition to the duplicate tab shortcut, this add-on offers several other useful shortcuts that can be customized and used simultaneously. Users can configure a shortcut to open a new tab in a new window, pop the current tab (or multiple tabs) out to a new window, and open a blank new tab next to the current tab instead of at the end.

Even without this extension, it is possible to duplicate the current tab by middle clicking the refresh button. However, Duplicate Tab Shortcut provides a more convenient and customizable way to achieve this.

For Firefox users, there is a separate version of the add-on available on the Mozilla Add-ons website. The source code for Duplicate Tab Shortcut is also available on GitHub for those interested in exploring or contributing to the project.