Bunker No. 46 is an abandoned military bunker that resides on Flame Rock Island. Inside, is Matty's army of Toaster-Bots. He says that one day the toaster bots will be threatning but that day is not today... or tomorrow.
During The Great Foo War, Bunker No. 46 was used as a shelter for wounded soldiers. Soldiers would be kept here for some time depending on how badly injured they were. After the war ended, the bunker was abandoned. and hasn't been touched until Matty took it.