kernel-preempt from home:mwilck:Leap:15.3 project
Select Your Operating System
Add repository and install manually
For pool run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mwilck:Leap:15.3/pool/home:mwilck:Leap:15.3.repo zypper refresh zypper install kernel-preempt