[cctbxbb] Inserting F000 into reflection (mtg) file

Hi Everyone, I’ve been looking through the cctbx/phenix scripts and although there’s a script for estimating F000 (phenix.f000), I can’t find any way of inserting it into an mtz file to make it accessible for easy map generation. Is this implemented anywhere/what do people use as the best way of doing this? If the insertion of F000 into an mtz file has been purposefully avoided, I presume it's done because we don't want the possibility of someone refining a model where F000 is used in refinement. Unless there’s another reason? Thanks, Nick