--proxy-tls13-ciphers

Same as --tls13-ciphers but used in HTTPS proxy context.

Specify which cipher suites to use in the connection to your HTTPS proxy when it negotiates TLS 1.3. The list of ciphers suites must specify valid ciphers. Read up on TLS 1.3 cipher suite details on this URL:

https://curl.se/docs/ssl-ciphers.html

This option is used when curl is built to use OpenSSL 1.1.1 or later, Schannel, wolfSSL, or mbedTLS 3.6.0 or later.

Before curl 8.10.0 with mbedTLS or wolfSSL, TLS 1.3 cipher suites were set by using the --proxy-ciphers option.