I'm not talking about cross-platform compatibility. It just seemed over-complicated. Yes, on Windows it is part of the PE file, which is based on UNIX System

I'm not talking about cross-platform compatibility. It just seemed over-complicated. Yes, on Windows it is part of the PE file, which is based on UNIX System V's COFF. These files have a list of sections used to distinguish between code, read only static data, read/write static data, optional debugging information, etc. The resources are just another section with the data in a particular format (probably not dissimilar in format to the Mac resource fork) and Windows has APIs to conveniently access the data. But one thing this can't do is attach resources to arbitrary file formats. Thank you, that's a use case I was unaware of.