mariabackup used to have this option (inherited from xtrabackup, surely), but not anymore. If it did what is documented for Percona xtrabackup, then it indeed doesn't make sense for mariabackup:
When launched with Version Check enabled, the tool that supports this feature connects to a Percona’s version check service via a secure HTTPS channel. It compares the locally installed version for possible updates, and also checks versions <...>
So it was probably the right way to remove it, although not very backward-compatible.
However, it is still documented in the KB, so it is a documentation bug to fix.
why did you use it? what result did you expect?