APT, Proxy-Auto-Detect et proxy.pac ou wpad.dat
The option Acquire::http::Proxy-Auto-Detect already exists for some time. It was intended to be used with the package squid-deb-proxy-client which is a helper for the APT http method to discover proxies that publish their service as _apt_proxy._tcp. It was justed upgraded (version 1.0.8) and now add the URL as a paramater. It is now possible to discover a common proxy through a proxy.pac script.