https://bugs.winehq.org/show_bug.cgi?id=43605
--- Comment #11 from raydongf@gmail.com --- (In reply to Sagawa from comment #10)
From my understanding, Wine doesn't support ECC algorithms. However, we can use ECDHE if GnuTLS supports it. So, the main issue is that we can't verify ECDSA (Digital Signature Algorithm) which is typically used in TLS 1.2 certificates.
Looks like GnuTLS does support both ECDHE and ECDSA, and if it's new enough, the TLS 1.3 ECDSA algorithms as well.