An extended article about 'drone swarms' thanks to a FOIA request being fulfilled. (It's The Drive, but they have based it on the documents furnished by the USN).
https://www.thedrive.com/the-war-zon...-new-documents
Drone warfare has been a topic of much study by the USN for well over a decade. I'd expect it to feature heavily in anything that crops up in the South China Sea.