Two folders for spam/junk in Sogo. why?

[Ret]

I wonder what's the difference between Junk folder and Spam folder in Sogo interface.
I think Junk comes with Sogo by default and Spam is created by Zentyal. Is there a way to unify and merge those two into only one? It's very confusing to our users.

I cannot seem to find where they are created in dovecot and/or sogo config files. Plus, It's not clear which is the folder spamassassin filter learns spam from.
Any help would be appreciated!