For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai/openSUSE_Factory/home:tiwai.repo
zypper refresh
zypper install vkeybd
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai/15.6/home:tiwai.repo
zypper refresh
zypper install vkeybd
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai/15.5/home:tiwai.repo
zypper refresh
zypper install vkeybd
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:tiwai/15.4/home:tiwai.repo
zypper refresh
zypper install vkeybd