What is it, a phrase or a clause?

The bolded words are a phrase. "Room" and "another," joined by a coordinating conjunction, are both direct objects of the verb "includes." "Labeled as an atrium" and "called a mudroom" are both participial phrases modifying the objects, respectively. As Camela G. says below, there is no subject-verb combination that would classify the bold words as a clause.
If you were to argue that there is an omitted relative pronoun, then where is the verb? "Labeled" is not the verb; it lacks the auxiliary "is" necessary to make a passive verb that would complement the omitted"that." Same with "called." Phrase.