Comment 3 for bug 107641

my own experience says :

inside the /etc/apt/sources.list.d directory ...
* if the files ends with '.list' then it is taken in account during a apt-get update
* if else not

Anyway, it is not so important because 'sources.list' ends with 'list'

I just wanted to warn for that because some 'edgy-universe.list' or 'medibuntu.list' appear now on ubuntu forums (particularly on forum.ubuntu-fr.org) and the manpage syntax is not respected

thanks for the time you gave to answer