For openSUSE Leap 15.4 Update standard run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mashatarasevich/openSUSE_Leap_15.4_Update_standard/home:mashatarasevich.repo
zypper refresh
zypper install openconnect
For SLE 15 SP6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mashatarasevich/SLE_15_SP6/home:mashatarasevich.repo
zypper refresh
zypper install openconnect
For SLE 15 SP4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mashatarasevich/SLE_15_SP4/home:mashatarasevich.repo
zypper refresh
zypper install openconnect