At least for me they are. My imports statements break and are not backwards compatible. I can appreciate code cleanup efforts. I end up with people who can only use my library if they update to Babylon.js latest… and I need to generate a new version myself. At least if you are aware of the downstream implications is maybe enough - mostly wanting to raise awareness. We’ve had these issues always, but much more pronounced and harder to maintain with the new release strategy.
Ie:
yes, changing filename is a breaking change. We should pay more attention to that.
It doesn’t really need to be a breaking change. I wonder if a policy like this would work - a temporary file could have an expiry date where it was deleted and cleaned up some point in the future. Just to keep some kind of continuum at least between major versions:
I see you’ve since marked as @internal, but it could be cleared up probably - depending if you have a retention policy.
@brianzinn, so sorry it impacted you. I remember thinking a long time about this one but as greased line is so new I did not thought it was already implemented in prod 
no worries. just more raising awareness. cheers.