I know theoretically this is a problem, and I've heard people make similar statements, but I'm having a failure of imagination at thinking of specifics. If you

I know theoretically this is a problem, and I've heard people make similar statements, but I'm having a failure of imagination at thinking of specifics. If you are using a fully open source toolchain what does the threat model actually look like in the real world? Even if a device itself is malicious, what can it actually do to exfiltrate information about what's happening inside it without being incredibly obvious? How can it know what register bits are even of interest given some configuration bitstream? It just seems like there are so many hypotheticals that it isn't worth being concerned about. Would love to be educated about this.