For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:cwh/openSUSE_Tumbleweed/home:cwh.repo
zypper refresh
zypper install stella
For openSUSE Leap 15.2 ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:cwh/openSUSE_Leap_15.2_ARM/home:cwh.repo
zypper refresh
zypper install stella
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:cwh/15.5/home:cwh.repo
zypper refresh
zypper install stella
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:cwh/15.4/home:cwh.repo
zypper refresh
zypper install stella