For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:Tumbleweed/openSUSE_Tumbleweed/home:frispete:Tumbleweed.repo
zypper refresh
zypper install apt-cacher-ng
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:Tumbleweed/15.5/home:frispete:Tumbleweed.repo
zypper refresh
zypper install apt-cacher-ng
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:frispete:Tumbleweed/15.4/home:frispete:Tumbleweed.repo
zypper refresh
zypper install apt-cacher-ng