typelib-1_0-Gdm-1_0 from isv:SUSE:suse-it-infra project
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Add repository and install manually
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/isv:SUSE:suse-it-infra/15.4/isv:SUSE:suse-it-infra.repo zypper refresh zypper install typelib-1_0-Gdm-1_0