For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Dead_Mozay/openSUSE_Tumbleweed/home:Dead_Mozay.repo
zypper refresh
zypper install grub-customizer
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Dead_Mozay/openSUSE_Slowroll/home:Dead_Mozay.repo
zypper refresh
zypper install grub-customizer
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Dead_Mozay/15.6/home:Dead_Mozay.repo
zypper refresh
zypper install grub-customizer
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:Dead_Mozay/15.5/home:Dead_Mozay.repo
zypper refresh
zypper install grub-customizer