Hi Thorsten,
I would expect apt.conf(5) to document any and all configuration items one can do to apt*, either directly or by other manpages referenced from “SEE ALSO”.
The man page of apt.conf shows the following: EXAMPLES/usr/share/doc/apt/examples/configure-index.gz is a configuration file showing example values for all possible options.
The file location is incorrect (on Debian sid), this should be /usr/share/doc/apt/examples/configure-index. It documents all the options you can find.
Cheers, Wesley -- Wesley Schwengle E: wesley@schwengle.net