FreeBSD and NetBSD also implement "-n". There doesn't seem to be a cross-platform port of OpenBSD cron like there are of doas and OpenBSD ksh. (Anybody want to try making one?) Cross-platform fcron has "erroronlymail".

https://man.freebsd.org/cgi/man.cgi?query=crontab&apropos=0&...

https://man.netbsd.org/NetBSD-9.3-STABLE/crontab.5

http://fcron.free.fr/doc/en/fcrontab.5.html#FCRONTAB.5.ERROR...