KiCad cannot connect with HTTPS system proxy enabled on macOS

Description

KiCad cannot connect to the internet when HTTPS system proxy is enabled on my Mac.

I use Surge, which sets both HTTP and HTTPS system proxies to 127.0.0.1:6152. KiCad connects to this port but then times out. No request appears in Surge.

HTTP-only and SOCKS-only settings work. Using TUN mode without system proxy also works.

The log shows that KiCad starts TLS negotiation with the proxy without sending CONNECT first. It seems to treat the HTTPS system proxy setting as a TLS connection to the proxy itself. It should use HTTP CONNECT to establish a tunnel instead.

Steps to reproduce

Create an empty project.
Enable Surge's system proxy with HTTPS proxy set to 127.0.0.1:6152. Keep TUN mode disabled.
Restart KiCad.
Open Plugin and Content Manager and load the repository.
The connection times out.

KiCad Version

Application: KiCad arm64 on arm64
Version: 10.0.6, release build
Libraries:
    wxWidgets 3.2.8 
    FreeType 2.14.3
    HarfBuzz 14.3.0
    FontConfig 2.18.2
    libcurl/8.7.1 (SecureTransport) LibreSSL/3.3.6 zlib/1.2.12 nghttp2/1.68.1
Platform: macOS Version 26.5.2 (Build 25F84), 64 bit, Little endian, wxMac
Build Info:
    Date: Aug 28 2026 14:40:19
    wxWidgets: 3.2.8 (wchar_t,wx containers)
    Boost: 1.90.0
    OCC: 7.9.3
    Curl: 8.7.1
    ngspice: 45.2
    Compiler: Clang 16.0.0 with C++ ABI 1002
    KICAD_IPC_API=ON
    KICAD_USE_PCH=OFF

Network Log

Started KiCad with:

KICAD_CURL_VERBOSE=1 /Applications/KiCad.app/Contents/MacOS/kicad 2>&1 | tee /tmp/kicad-network.log

Click to expand

* Trying 127.0.0.1:6152...
* Connected to 127.0.0.1 (127.0.0.1) port 6152
* ALPN: curl offers http/1.1
* CAfile: /etc/ssl/cert.pem
* CApath: none
* SSL connection timeout
* Closing connection
* Trying 127.0.0.1:6152...
* Connected to 127.0.0.1 (127.0.0.1) port 6152
* ALPN: curl offers http/1.1
* CAfile: /etc/ssl/cert.pem
* CApath: none