curl/docs/cmdline-opts/proxy-key-type.md

c	SPDX-License-Identifier	Long	Arg	Help	Added	Category	Multi	See-also	Example
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.	curl	proxy-key-type	<type>	Private key file type for proxy	7.52.0	proxy tls	single	proxy-key proxy	--proxy-key-type DER --proxy-key here -x https://proxy.example $URL

--proxy-key-type

Specify the private key file type your --proxy-key provided private key uses. DER, PEM, and ENG are supported. If not specified, PEM is assumed.

Equivalent to --key-type but used in HTTPS proxy context.