with his ref to satan/cults and the keystone, the papal insignia is a key, which is on the rock of the vat. The key is supposed to represent the key to the abyss in which lies the dragon, the deceiver.
http://www.authorstream.com/Presentation/rlhodge33-1524107-papal-stargate-key-abyss-pt-24/
https://promusement.live/2016/04/08/pope-francis-as-the-key-to-the-age/
https://www.wsj.com/articles/vatican-denounces-accusation-against-pope-but-confirms-key-point-1538912551