Project War-Mantle, which involved the conscription and training of non-clone troopers for the Empire, was first mentioned in Rogue One: A Star Wars Story (2016) when Jyn Erso and Cassian Andor were searching for the code name of the Death Star plans on Scarif.
The Aurebesh text visible on the viewscreen on the Havoc Marauder that Hunter looks at translates to "Capacitor not found".
The area of the Havoc Marauder that Wrecker has converted into a bedroom for Omega used to serve as the ship's top gun-port.