Understanding hobbit

Hello. 

There are a few things I dont quite understand yet about hobbit and I
cant find anything that explains it in the docs so i better ask :)

In the hobbit "display", the webpage, the hobbit server itself is listed
with a few things i dont get on the other servers, like bbd, bbgen,
bbtest and hobbitd. These seem to provide interesting things though. I
have installed hobbit-client on the clients. 

Regards,
Benedikt