$ git clone -n https://src.fedoraproject.org/rpms/snapshot.git /var/lib/mock/f40-build-2662716-66955/root/chroot_tmpdir/scmroot/snapshot
Cloning into '/var/lib/mock/f40-build-2662716-66955/root/chroot_tmpdir/scmroot/snapshot'...
$ git fetch origin 02abee14754f9edbd342b461dbfc1802bdab3712:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/snapshot
 * [new ref]         02abee14754f9edbd342b461dbfc1802bdab3712 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 02abee1 Update to 46.0