$ git clone -n https://src.fedoraproject.org/rpms/rubygem-progressbar.git /var/lib/mock/f45-build-35163-693/root/chroot_tmpdir/scmroot/rubygem-progressbar
Cloning into '/var/lib/mock/f45-build-35163-693/root/chroot_tmpdir/scmroot/rubygem-progressbar'...
$ git fetch origin 6b4c32487a29ed566e83f7fd7ca3bffb5c7d0e6a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-progressbar
 * [new ref]         6b4c32487a29ed566e83f7fd7ca3bffb5c7d0e6a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b4c324 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild