WebKitGTK-shaped — set HTTP(S) proxy for this session.
On Windows, the first CUSTOM before any WebView is shown starts the library local host proxy and every later view’s environment points at it (http://127.0.0.1:port). Chromium has no userinfo in that URI; the first CONNECT gets 407 and BasicAuthenticationRequested supplies the view id as Basic user. Dummy http://127.0.0.1 and no table row are pass-through. Any other URI is a live relay for this session. CUSTOM after a shared environment (no local host proxy) already exists is an error.