With Android 11, Google introduced a feature that would automatically revoke the permissions of unused apps. With the next major upgrade, Android 12, Google may expand that feature and automatically put these apps to sleep. Not only that, but "temporary files", which probably indicate cache files, compilation objects and the like from the unused apps, can be removed to free up storage space.
New life for well-stocked phones
In January, code was discovered in the Android Open Source Project Gerrit which indicated that the developers are working on such a feature.
In the version tested by XDA Developers, a mobile software development community, you must enable the "Remove permissions and free up space" option in "Unused apps". The option was present in "Appinfo" for each installed app. The pictures below from left to right show the procedure.
While the auto-sleep and space-saving features are interesting and certainly useful especially for Android users with budget phones and limited storage space - or as a general battery-saving tool - we do not know what Google will end up with in the final version.