Proxy-Authorization header missing iOS/MacOS Safari HTTPS

I am trying to create a proxy server which authenticates the connecting users. I've managed to successfully create a proxy server for Firefox with authentication but whenever I try the exact same proxy details in my Mac or iOS, it keeps asking for the username and password.

I've noticed that iOS/Mac does not send the https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Proxy-Authorization header for secure requests. It does for insecure HTTP requests however, so insecure requests are working fine.

Can anyone explain how iOS/Mac HTTPS proxy authorization works? As I don't see any header indicating authorization.
Proxy-Authorization header missing iOS/MacOS Safari HTTPS
 
 
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