$ git clone -n https://src.fedoraproject.org/rpms/rubygem-color.git /var/lib/mock/f45-build-34826-691/root/chroot_tmpdir/scmroot/rubygem-color
Cloning into '/var/lib/mock/f45-build-34826-691/root/chroot_tmpdir/scmroot/rubygem-color'...
$ git fetch origin bd5e06d75bf7f86ff7beaf993bbeefd4825880f9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-color
 * [new ref]         bd5e06d75bf7f86ff7beaf993bbeefd4825880f9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bd5e06d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild