I am a little confused about this. I had never heard of it, so have been
looking it up. There is no man entry, and the man apt entry, which mentions
and gives hyperlinks to toher apt applications (apt-cache etc.) does nto
mention it.
Googling brings up the information that Potato users used to use it to
configure their /etc/apt/sources.list, and the installer still uses it for
the same purpose. But I could find no trace of any recent usage by users
wanting to (re)configure their sources.list. Comments gratefully received!
Lisi