For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:D/openSUSE_Tumbleweed/devel:languages:D.repo
zypper refresh
zypper install tilix
For openSUSE Leap 15.2 ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:D/openSUSE_Leap_15.2_ARM/devel:languages:D.repo
zypper refresh
zypper install tilix
For openSUSE Factory ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:D/openSUSE_Factory_ARM/devel:languages:D.repo
zypper refresh
zypper install tilix