I think Dark theme must be enabled by an admin:
And, yeah, i did miss that undelete thingy, so you beat me to the Badge. 
Thanks anyway 
The Bot sends you a message at the very beginning. My problem was, i could not scroll down to the first messages, so i couldnt find it anymore.
People must find this thread in order to know how to talk to the @discobot if they missed it in the first place.