For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio:python3/openSUSE_Tumbleweed/home:illuusio:python3.repo
zypper refresh
zypper install borgmatic
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio:python3/15.5/home:illuusio:python3.repo
zypper refresh
zypper install borgmatic
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio:python3/15.4/home:illuusio:python3.repo
zypper refresh
zypper install borgmatic