--proxy-ciphers

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

Specify which cipher suites to use in the connection to your HTTPS proxy when it negotiates TLS 1.2 (1.1, 1.0). The list of ciphers suites must specify valid ciphers. Read up on cipher suite details on this URL:

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