yast2-mail from YaST:SLE-15:GA project
Select Your Operating System
Add repository and install manually
For SLE 15 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/YaST:SLE-15:GA/SLE_15/YaST:SLE-15:GA.repo zypper refresh zypper install yast2-mail