> I suppose the mentioned structures were used to hold the different bits of code, while sharing e.g. text strings that were loaded in .text or whatnot. I don'

> I suppose the mentioned structures were used to hold the different bits of code, while sharing e.g. text strings that were loaded in .text or whatnot. I don't believe so: universal ("fat") binaries are basically a container type, with N fully independent contained Mach-O slices. It isn't even compressed; each architecture's binary is just mashed into the file, one after another.