$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gio2.git /var/lib/mock/f38-build-728391-101203/root/chroot_tmpdir/scmroot/rubygem-gio2
Cloning into '/var/lib/mock/f38-build-728391-101203/root/chroot_tmpdir/scmroot/rubygem-gio2'...
$ git fetch origin 105c5328af398d2170d873b470f80a47f2107602:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-gio2
 * [new ref]         105c5328af398d2170d873b470f80a47f2107602 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 105c532 4.1.7 entry