The SLES 15 SP4 release notes explicitly mention fail2ban being added to the
Basesystem module:
https://www.suse.com/releasenotes/x86_64/SUSE-SLES/15-SP4/index.html#jsc-SLE-11611
> 5.11.4 fail2ban has been added
> The fail2ban package has been added to the Basesystem Module. It is used to ban addresses that make too many authentication failures, based on scanning various log files.

I expected this to apply to openSUSE Leap 15.4 as well, especially that Leap is
now shipping SLES binaries since 15.3.  Unfortunately on a Leap 15.4 system,
fail2ban is nowhere to be found according to 'zypper search'.

Is this an oversight, or an intentional omission?  I would hope everything
shipped in SLES (at least the modules which aren't a separate subscription) was
also available in the corresponding release of Leap, except for obvious things
like branding and subscription management.