Drives are classified as RPC-1 (region changeable) or RPC-2 (region locked). All current drives are RPC-2 and have been for more years than I can remember.
However Region Codes are controlled by software which is why official players such as
PowerDVD exist to change the Region (limited to 5 times per drive and then you require another program to clear that setting) or programs such as
DVDFab Passkey which effectively makes the drive Region Free.
However software players such as
vlc ignore Region Codes and will play
any dvd.