For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jloeser:secureboot/openSUSE_Tumbleweed/home:jloeser:secureboot.repo
zypper refresh
zypper install efitools
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jloeser:secureboot/openSUSE_Factory/home:jloeser:secureboot.repo
zypper refresh
zypper install efitools
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jloeser:secureboot/15.5/home:jloeser:secureboot.repo
zypper refresh
zypper install efitools
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jloeser:secureboot/15.4/home:jloeser:secureboot.repo
zypper refresh
zypper install efitools