$ git clone -n https://src.fedoraproject.org/rpms/libical.git /var/lib/mock/f40-build-1239599-22917/root/chroot_tmpdir/scmroot/libical
Cloning into '/var/lib/mock/f40-build-1239599-22917/root/chroot_tmpdir/scmroot/libical'...
$ git fetch origin 99cfed3610b79a810c4f83cc638d58dd41d808a7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libical
 * [new ref]         99cfed3610b79a810c4f83cc638d58dd41d808a7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 99cfed3 Update to 3.0.18