Apple deprecated OpenSSL in macOS some time ago, directing people to their Core Crypto framework instead.

See http://stackoverflow.com/questions/7406946/why-is-apple-depr... for more info and links

it's not quite true - on latest macOS (10.14.5), on openssl based on LibreSSL 2.6.5 there's complete man page available - but, the funniest thing, it's dated on... today