Which version is the samba one? Latest release? Git?
If you want to see the man page of the version in Debian, that would be https://manpages.debian.org/testing/rsync/rsync.1.en.html
Disclaimer: I wrote the software behind manpages.debian.org :)
linux.die.net is horribly outdated. This particular page is from 2009.
Up-to-date docs are here:
https://download.samba.org/pub/rsync/rsync.1