I did this

In #19812 after fixing Unix socket test servers, I applied Stefan's patch #19810
to use absolute Unix socket filenames. This lead to this error:

curl.exe ... --socks5 localhostD:/a/curl/curl/bld/tests/log/8/server/socks-uds ...
=== Start of file trace1467
 15:15:41.269000 * !!! WARNING !!
 15:15:41.269000 * This is a debug build of libcurl, do not use in production.
 15:15:41.269000 * alloc connection, bits.close=0
 15:15:41.269000 * Unsupported proxy scheme for 'localhostD:/a/curl/curl/bld/tests/log/8/server/socks-uds'
 15:15:41.269000 * closing connection #-

https://github.com/curl/curl/actions/runs/19898592049/job/57035659366?pr=19812#step:13:2682

Using a relative path, e.g. --socks5 localhost/tmp/curl-socksd-xe3LMbVY,
doesn't have this issue, but it's not an absolute filename on Windows, and the
Unix socket is not found:
https://github.com/curl/curl/actions/runs/19896583933/job/57028545111?pr=19812

Bug: #19810 (comment)
Possibly related patch dfa84a0 #8668

I expected the following

option --socks5 localhostD:/a/curl/curl/bld/tests/log/8/server/socks-uds to set the endpoint to D:/a/curl/curl/bld/tests/log/8/server/socks-uds.

Or another (standard) naming scheme with the same effect:

--socks5 localhost/d/a/curl/curl/bld/tests/log/8/server/socks-uds or --socks5 D:/a/curl/curl/bld/tests/log/8/server/socks-uds perhaps?

curl/libcurl version

curl 7.84.0+ (when this feature was introduced) up to latest master.

operating system

Windows 10.17063+ (having Unix socket support)