Drupal Toolbar Toggle od Anders Pedersen

Drupal Toolbar Toggle is a lightweight Firefox extension that makes it easy to hide and show the Drupal 11 admin toolbar (elements with the .toolbar class) on the current page.

It is designed for developers and content editors who want more screen space while working on layout, styling, or debugging.

Features:

Toggle toolbar visibility by clicking the extension icon
Keyboard shortcut for fast access (Alt+Shift+T)
Also removes the extra body top padding when the toolbar is hidden
Restores both the toolbar and the previous body top padding on the next toggle
Privacy:

The extension does not collect data
The extension does not send data to external services
All functionality runs locally in the browser