https://bugs.winehq.org/show_bug.cgi?id=45810
--- Comment #6 from Jason Edmeades us@edmeades.me.uk --- Yeah its odd... I'm proposing a patch which takes it up to 2048 (which the intel article indicates is the part at where the o/s behaves oddly). Windows 10 certainly allows longer values in the env vars via the registry (setx is self limiting as per some of the articles), and the truncation doesnt feel like behaviour that any app can be relying on anyway.
I've added it to my local patches and will submit within a week or so (I have others I'm working on), and see whether it gets in or gets shot down :-)
Interesting project too btw :-)