The Soviets planted listening devices in American embassy typewriters between October 1976 and January 1984 - by intercepting them in the mail!
Really sophisticated devices: https://www.cryptomuseum.com/covert/bugs/selectric/
I love the internet. For all its drawbacks lately, deep down at its core, there are still hidden gems out there like this website. There goes my afternoon.
Wow, back in the 70s the bugs were only detectable by x-ray scan. Makes you wonder what kinds of things can be hidden in the ICs of today.