$ git clone -n https://src.fedoraproject.org/rpms/openvdb.git /var/lib/mock/f40-build-1495740-23855/root/chroot_tmpdir/scmroot/openvdb
Cloning into '/var/lib/mock/f40-build-1495740-23855/root/chroot_tmpdir/scmroot/openvdb'...
$ git fetch origin 3e2a0e796c0565381a2edfb6c1284c3904fe4ab7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/openvdb
 * [new ref]         3e2a0e796c0565381a2edfb6c1284c3904fe4ab7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3e2a0e7 Fix tbb requirement for devel subpackage (rhbz#2296365)