For openSUSE Leap 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:msvec/openSUSE_Leap_15.6/home:msvec.repo
zypper refresh
zypper install mc
For openSUSE Leap 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:msvec/openSUSE_Leap_15.5/home:msvec.repo
zypper refresh
zypper install mc
For openSUSE Leap 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:msvec/openSUSE_Leap_15.4/home:msvec.repo
zypper refresh
zypper install mc