https://bugs.winehq.org/show_bug.cgi?id=55105
--- Comment #4 from Ethan Lee flibitijibibo@gmail.com --- Someone did a bit of digging and found that the Proton 7.0 branch successfully logged in, which was surprising - it turns out there are a few patches that made it work:
https://github.com/ValveSoftware/wine/commit/d8c2086d0e34450c9b8b5a85466a307... https://github.com/ValveSoftware/wine/commit/6d4dbf0762863f6f1f9dc4738258e98... https://github.com/ValveSoftware/wine/commit/7f18691e39d8de6668e3451f63b0326...
Interestingly this is _not_ in the 8.0 branch, so in addition to being downstream it seems like they got cut for some reason. These appear to bypass the CERT_NEEDED error altogether in favor of just renegotiating as soon as gnutls asks for it.