As to my understanding GP has bought the right to manufacture the AS (Anton Schild) 5008 which is derived from a vintage alarm movement and with able to have modification like gmt, worldtime. Then GP can claim is own manufacture movement and also sell it to others brands. The brands that used this movement like B&M, ML, Oris and others.
There are basically 4 famous alarm manufacturer like JLC, AS by GP, Vulcain and Lemania (Breguet)
Just go to google and search AS 5008 for more details.