I thought this was about running windows 9x within linux. Is there such thing without virtualisation?

You can setup handlers to automatically launch windows executables using wine/proton .

This trickery is called binfmt_misc , which is a linux kernel system to associate random binary files with custom userspace 'interpreters'

I have had it working in the past. And while it is kinda neat I prefer manually running 'wine program.exe' to have a bit more control.

I have seen reports that a binfmt_misc setup + wine is good enough to get infected by certain windows viruses ;-P