For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tdz:branches:home:mcepl/openSUSE_Tumbleweed/home:tdz:branches:home:mcepl.repo
zypper refresh
zypper install quilt
For openSUSE Factory zSystems run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tdz:branches:home:mcepl/openSUSE_Factory_zSystems/home:tdz:branches:home:mcepl.repo
zypper refresh
zypper install quilt
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tdz:branches:home:mcepl/15.6/home:tdz:branches:home:mcepl.repo
zypper refresh
zypper install quilt
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tdz:branches:home:mcepl/15.5/home:tdz:branches:home:mcepl.repo
zypper refresh
zypper install quilt