Project: QGIS
Version: 3.18
A new "View Settings" tab has been added to the project properties, with the option to manually defined the full extent of a project. The extent defined here will be the extent used when zooming to the full map extent, instead of the calculated or maximum extent of all layers. This is useful for defining a particular area of interest for a project and does not limit user's ability to "zoom out" further than the defined extent.
This feature was developed by Nyall Dawson