$ git clone -n https://src.fedoraproject.org/rpms/rubygem-clutter-gtk.git /var/lib/mock/f40-build-2679193-67929/root/chroot_tmpdir/scmroot/rubygem-clutter-gtk
Cloning into '/var/lib/mock/f40-build-2679193-67929/root/chroot_tmpdir/scmroot/rubygem-clutter-gtk'...
$ git fetch origin a241d2ee6520e31933daed5ab949be5cb8d0ae93:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-clutter-gtk
 * [new ref]         a241d2ee6520e31933daed5ab949be5cb8d0ae93 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a241d2e 4.2.2 entry