$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gio2.git /var/lib/mock/f45-build-34939-692/root/chroot_tmpdir/scmroot/rubygem-gio2
Cloning into '/var/lib/mock/f45-build-34939-692/root/chroot_tmpdir/scmroot/rubygem-gio2'...
$ git fetch origin 39a19137890424a860a73d5461f220964c714d33:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-gio2
 * [new ref]         39a19137890424a860a73d5461f220964c714d33 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 39a1913 4.3.8 entry