yast2-bootloader from openSUSE:Leap:42.3:Update project
Select Your Operating System
Add repository and install manually
For standard run the following as root:
zypper addrepo https://download.opensuse.org/repositories/openSUSE:Leap:42.3:Update/standard/openSUSE:Leap:42.3:Update.repo zypper refresh zypper install yast2-bootloader
For ports run the following as root:
zypper addrepo https://download.opensuse.org/repositories/openSUSE:Leap:42.3:Update/ports/openSUSE:Leap:42.3:Update.repo zypper refresh zypper install yast2-bootloader