Update: They must have added more content to Profiles in Cubase 15 than it is acknowledged in the documentation:
I temporarily renamed all preference folders from Cubase 13 to Cubase 15 (otherwise Cubase 15 would extract preferences from previous versions) and activated my latest profile. After relaunching Cubase all configuration presets as well as control room presets reappeared although there was no folder to extract them from. So, I assume they must have been extracted from the profile because they weren’t there in the first place after renaming the preference folders. They also showed up as separate preset files after relaunchning Cubase a second time after activating the profile.
All the more reason for me to update my profile once in a while 
And yes, it would be nice if the manual kept us informed with updates… same old same old. It’s a brilliant feature like many others that are hidden in Cubase without Steinberg promoting it.