I'm finding the recent Veritasium videos are a bit weird... they mention a recent "thing 1", then do a super-deep historical dive into a somewhat related "thing 2" (presenting it as "the origins of thing 1").

This one [1] is "The Secret Spy Tech Inside Every Credit Card", where they briefly poke at NFC and then wind back to talk about the Soviet's listening device, gifted to the US Ambassador in 1945 [2].

They explain in some detail how the device works, showing it as what many woud recognise as Frequency Modulation, before calling it Amplitude Modulation(?!)

... the Wiki page states "the membrane and the post formed a variable capacitor acting as a condenser microphone and providing amplitude modulation (AM), with parasitic frequency modulation (FM) for the re-radiated signal", which is... I mean... okay, I guess... but isn't any FM broadcast actually AM too by this definition?

1: https://www.youtube.com/watch?v=YSJY3DvnybE

2: https://en.wikipedia.org/wiki/The_Thing_(listening_device)