observatory-cli is the command-line version of Mozilla's Observatory, »a project designed to help developers, system administrators, and security professionals configure their sites safely and securely.«

»ALPACA is an Application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. Attackers can redirect traffic from one subdomain to another, resulting in a valid TLS session.«

acme.sh is an ACME protocol client written purely in Shell (Unix shell) language.

Deprecating TLS 1.0 and TLS 1.1

Add kernel-side support for in-kernel TLS.

s. also https://wiki.mozilla.org/Security/Server_Side_TLS

HTTPSWatch tracks the HTTPS support of prominent websites.

http://neverssl.com/