xcb-shim: easier native X11 protocol implementation

That could be one use, yes. There's a whole spectrum of options available for that kind of thing! You could pop Squeak SystemWindows out into separate X11 windows; you could make Squeak the X window manager; etc.

I'm currently putting Squeak as the desktop environment for a cellphone [1,2,3], and in order to get non-Squeak apps like a browser etc running in a non-terrible way, I need to be able to talk to X.

[1] https://eighty-twenty.org/tag/squeak-phone/ [2] https://syndicate-lang.org/journal/tag/squeak-phone/ [3] https://git.syndicate-lang.org/tonyg/squeak-phone