$ git clone -n https://src.fedoraproject.org/rpms/gnome-chemistry-utils.git /var/lib/mock/f39-build-1599046-38512/root/chroot_tmpdir/scmroot/gnome-chemistry-utils
Cloning into '/var/lib/mock/f39-build-1599046-38512/root/chroot_tmpdir/scmroot/gnome-chemistry-utils'...
$ git fetch origin a0a1fb3f1cc2c78745231e66352490c2dc5633f9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-chemistry-utils
 * [new ref]         a0a1fb3f1cc2c78745231e66352490c2dc5633f9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a0a1fb3 Rebuild