$ git clone -n https://src.fedoraproject.org/rpms/libxml++30.git /var/lib/mock/f45-build-17340-498/root/chroot_tmpdir/scmroot/libxml++30
Cloning into '/var/lib/mock/f45-build-17340-498/root/chroot_tmpdir/scmroot/libxml++30'...
$ git fetch origin 04e2bf6e83e910dadeadd63145540d34fb3ca3ec:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libxml++30
 * [new ref]         04e2bf6e83e910dadeadd63145540d34fb3ca3ec -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 04e2bf6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild