Authority of Steem Dev Team?

Hi all, I heard the "Nijeah" news and just got curious how this whole Steem Blockchain could be frozen by Steem Dev team. I am not trying to blame their action at all. Truly believe that Steem Dev team did a perfect job.

But as a student studying blockchain, I want to know the governance process. Does Steem Dev team hold significant amount of Steem? Or did the witnesses agreed to stop the block creation process and called for help?

Thank you, in advance. God bless.