$ git clone -n https://src.fedoraproject.org/rpms/libxml++30.git /var/lib/mock/f40-build-2201204-51812/root/chroot_tmpdir/scmroot/libxml++30
Cloning into '/var/lib/mock/f40-build-2201204-51812/root/chroot_tmpdir/scmroot/libxml++30'...
$ git fetch origin e6ccda48ed5cab890ff1c0df79576d2a3358ca9c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libxml++30
 * [new ref]         e6ccda48ed5cab890ff1c0df79576d2a3358ca9c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e6ccda4 Fix building against libxml2 2.12.0 and above