Topic on Store talk:Steam
The console has some interesting commands, such as ones to list all the subscriptions you have, the config of a game, and downloading individual depots. It can also be used to change some variables within Steam. It's not recommended for the end user to try, as they could bork things, and the commands are not documented with any amount of detail. I remember Steam.cfg
from some Steam hacking site a bunch of years ago, and it is actually still used now (for Steamworks developers so they can test their builds).