How to change engine (library) install location?

Just installed 4.18, but I accidentally put it in the wrong folder. I moved it (the “UE_4.18” folder) to the correct folder, assuming there would be a way to tell the launcher where the new location is during the “repair” process, but I couldn’t find it.

So the only recourse is to delete it and reinstall? This is lame; it’s already there, I shouldn’t have to waste time and bandwidth downloading the entire engine again, just to change its location!

So… how does the launcher know where the library path is? Config file? Registry? There should be something somewhere that can easily be edited…