For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:SLES/15.6/home:frispete:SLES.repo
zypper refresh
zypper install rsyslog
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:SLES/15.5/home:frispete:SLES.repo
zypper refresh
zypper install rsyslog
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:SLES/15.4/home:frispete:SLES.repo
zypper refresh
zypper install rsyslog
For 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:SLES/15.3/home:frispete:SLES.repo
zypper refresh
zypper install rsyslog