: Though I
: expect M1 films will still be a problem.
Unfortunately that's true. When Treellama got M2 film compatibility working, he traced one issue to a tiny (one-line) utility function that clamped a number to a given range. That function got left out of the M2 source release, so the Aleph One devs wrote their own. The replacement turned out to be just different enough to lead to out-of-sync deaths in a number of films: the Infinity release included Bungie's version and showed where Aleph One went wrong. So in that case, even the release of 99% of the source wasn't good enough for film compatibility!