Disable all renegotiation in TLSv1.2 and earlier. Do not send HelloRequest messages, and ignore renegotiation requests via ClientHello.
This option is only available with OpenSSL 1.1.0h and later.
New in version 3.7.
This is to handle vulnerability in ssl renegotiation which is disabled by default in TLSv1.3. It's not clear if openSSL is vulnerable: