$ git clone -n https://src.fedoraproject.org/rpms/rubygem-pango.git /var/lib/mock/f40-build-2639282-66351/root/chroot_tmpdir/scmroot/rubygem-pango
Cloning into '/var/lib/mock/f40-build-2639282-66351/root/chroot_tmpdir/scmroot/rubygem-pango'...
$ git fetch origin 224e0ffcecd70d03ff050045facce8014000f76c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-pango
 * [new ref]         224e0ffcecd70d03ff050045facce8014000f76c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 224e0ff 4.2.1 entry