The K Desktop Environment

4.21. What files can I delete from my KDE install directory? Can all the *.h, *.c and *.o files be safely removed?

There shouldn't be any need to keep the .c and .o files, but you might want to keep the .h files, as they are used by includes if you ever want to compile your own KDE programs. Or if you wish to add patches to the source programs as they become available (rather than downloading everything again), then they should stay.