Specifically, in this pagehttps://www.vasp.at/wiki/index.php/LORBIT, it is said:
ENMAX and ENMIN are only defined in POTCAR (which usually should not be touched). I believe the correct ones should be `EMIN` and `EMAX`.This is done in such a way that the new projector is optimally chosen to represent the calculated orbitals in the energy interval specified by ENMAX and ENMIN.