That's just not realistically possible beyond simple stacks of blended layers - and even then there are corner cases where two implementations will end up compu

That's just not realistically possible beyond simple stacks of blended layers - and even then there are corner cases where two implementations will end up computing different final composites. Anything nondestructive within a file format is almost always tied to the exact algorithm implementation of the program in which the file was created. Sometimes even swapping the order of commutative or associative mathematical operations for the same formula will lead to different results. I tried to make non-destructive workflows work in other contexts. It is probably not appreciated hard this is. It's easy to get yourself painted into a corner because if a file format says "apply operation x with these parameters", you are now stuck with shipping this operation x with all future versions of the software, even if you come up with a version 2.0 of x that is better, but not quite the same somehow. And if you want that software to keep a sane UI, it must hide that implementation detail of multiple versions of internal stuff somehow, usually with some kind of nasty hack. Especially open source programs are quite notorious for shying back from that because cruft like that is not fun to write or maintain.