@User For example, the fact that LEF is pretty much a cut back GDS with a little of extra annotation is super weird to me -- but it comes from the fact that in many cases people who get the LEF don't get access to the GDS

well there is that and then the need to control your own format to quickly adapt to non stopping crazy customer requirements… I guess solving this 20 years later should have an advantage as well

It's sort of the equivalent of the header file for a binary library AFAICT.