That's interesting in this context because GOG first started off getting good old games to work on modern hardware. I would also say that emulation of hardware has come a long ways, so a DRM-free executable may be all that you need for historic preservation, barring software that requires communicating with a server for its functionality.

And even if source code is provided, it can be next to impossible to build it on your machine, so hopefully it has a docker image or what have you. Would also need to know the GPU requirement to compile it.

Not saying I wouldn't want the source code to be provided, but I'd like it purely for research and modding purposes, not to make sure I can build from source 10 years from now.