in reality a bunch of stuff no user ever has to look at. On Windows literally anyone can click on a 20 year old executable and in all likelihood it just works because the good people at Microsoft care about giving the user a decent supply of libraries and stable ABIs and an actual operating system people can build against.

The Linux world is just in complete shambles in this regard. You build something on one LTS release, you don't know if it executes on the next. As the joke goes (it isn't even really a joke), it's so bad that Win32 is the only stable ABI on Linux