$ git clone -n https://src.fedoraproject.org/rpms/libguestfs.git /var/lib/mock/f40-build-739051-108618/root/chroot_tmpdir/scmroot/libguestfs
Cloning into '/var/lib/mock/f40-build-739051-108618/root/chroot_tmpdir/scmroot/libguestfs'...
$ git fetch origin 15f0fe6b038698433aeae0791ef9c7d8e4f8d44e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libguestfs
 * [new ref]         15f0fe6b038698433aeae0791ef9c7d8e4f8d44e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 15f0fe6 Use dhcpcd instead of dhclient (RHBZ#2247057)