How can I diagnose DNS resolution and TLS certificate validation failures in Emacs when retrieving packages from HTTPS archives?
When Emacs attempts to fetch package archives over HTTPS using the built-in url library, it relies on system DNS resolution and GnuTLS for certificate validation. If either step fails, Emacs aborts the operation and reports a generic TLS error, making it hard to pinpoint whether the problem lies in name resolution or in the certificate chain. The goal is to