This code seems to be unused for a long time or was never used at all.
Introduced in 2013 there were no substantial commits to it afterwards,
nor is the functionality exposed to the Ui.
Profiles were supposed to allow various screen layouts per single setup, for instance, if you have your monitor and TV both connected to your PC, you may want to have "Monitor", "Monitor+TV" and "TV-only" profiles. The idea was to have a combobox in the KCM that would allow you to quickly switch between those profiles without having to fiddle with the rest of the GUI every time. IIRC we did not agree with @afiestas on this feature back then, so it remained disabled (should've been on a branch instead of #ifdefs on master, I admit that ) and while I was still working on kscreen, I never got around to actually finish it and push it.
I remember Alex at the time had a thing that new features should be in master but in #ifdefs so it's easier for other devs to test things than having a giant patchset that no-one can even find and have to keep switching between.
It's not a bad idea, I never run code in branches for a long time.
However, it doesn't work if things get abandoned and die.