For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/openSUSE_Tumbleweed/devel:microos.repo
zypper refresh
zypper install rebootmgr
For openSUSE Factory zSystems run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/openSUSE_Factory_zSystems/devel:microos.repo
zypper refresh
zypper install rebootmgr
For openSUSE Factory PowerPC run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/openSUSE_Factory_PowerPC/devel:microos.repo
zypper refresh
zypper install rebootmgr
For openSUSE Factory ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/openSUSE_Factory_ARM/devel:microos.repo
zypper refresh
zypper install rebootmgr
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/15.6/devel:microos.repo
zypper refresh
zypper install rebootmgr
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:microos/15.5/devel:microos.repo
zypper refresh
zypper install rebootmgr