'Z0' is used as a null-move marker by some PGN file sources. This appears to be an alternative to '--' used for the same purpose by other PGN file sources and already accepted as a valid token.
'--' is treated as an error, because the movetext does not describe a game, and 'Z0' will be treated as an error too.
Currently 'Z0' is treated as the illegal token 'Z' followed by text starting with the move number character '0'.
'Z0' is used as a null-move marker by some PGN file sources. This appears to be an alternative to '--' used for the same purpose by other PGN file sources and already accepted as a valid token.
'--' is treated as an error, because the movetext does not describe a game, and 'Z0' will be treated as an error too.
Currently 'Z0' is treated as the illegal token 'Z' followed by text starting with the move number character '0'.