Has also previewed

There will likely be other pre-trial disputes over discovery that Nichols will need to resolve. Bannon's team has also previewed an effort to obtain additional internal documents -- beyond what already has been turned over to him -- from Congress, as well as records related to the Justice Department's decision to charge him. Prosecutors have signaled that they do not think Bannon is entitled to those additional documents."

CNN.

Is "has" a main verb or the auxiliary one in the second sentence in the paragraph above?