Subject: Re: bug#24396: 25.1; Doesn't trust Let's Encrypt certificates (used by MELPA)

From: Glenn Morris <[email-masked]>
Date: Fri, 09 Sep 2016 15:55:48 -0400

http://emacs.stackexchange.com/questions/18045/how-can-i-retrieve-an-https-url-on-mac-os-x-without-warnings-about-an-untrusted

seems relevant.

I guess OS X uses some system keychain for SSL certs that is opaque to Emacs.
Perhaps it should learn to understand it, if that's even possible.

There's a suggested workaround related to libressl there.