Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio:python/openSUSE_Tumbleweed/home:illuusio:python.repo
zypper refresh
zypper install python-rcssmin
Для 15.5 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio:python/15.5/home:illuusio:python.repo
zypper refresh
zypper install python-rcssmin
Для 15.4 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:illuusio:python/15.4/home:illuusio:python.repo
zypper refresh
zypper install python-rcssmin