$ git clone -n https://src.fedoraproject.org/rpms/libxml++50.git /var/lib/mock/f45-build-17322-498/root/chroot_tmpdir/scmroot/libxml++50
Cloning into '/var/lib/mock/f45-build-17322-498/root/chroot_tmpdir/scmroot/libxml++50'...
$ git fetch origin f8293443af28dc43863deee2a8b1662f3cfa6df5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libxml++50
 * [new ref]         f8293443af28dc43863deee2a8b1662f3cfa6df5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f829344 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild