That's kinda like being into sports (maybe even professionally) and comparing oneself to an Olympic champion. It's great to be inspired by them, but it's very important not to be discouraged by what they achieved. We are all standing on the shoulders of giants.

Seems strange to me to feel imposter syndrome for not matching up to an elite talent… did you feel prior to this that you were the best in the world at programming, and now realize you aren’t? Is everyone who isn’t the very top of the top an imposter?

Maybe he is smart and could do it but he is just very lazy and prefers to lie in bad playing games. That would cause him to feel that way when he realises that he could do more ;)

People use that term casually, don't read too much into the implications.

And TinyC, and the Bellard formula for calculating pi.

... and a fully working SDR implementation of the LTE phone standard.

The dude can wrap his head around literally anything. Him and Torvalds are truly exceptionally capable people.

Okay, here's a crazy idea.

The things he built are:

ffmpeg, which basically implements a bunch of specs for codecs

Qemu, which basically implement a bunch of specs for CPUs

TinyC / QuickJS, which basically implement a bunch of specs, mainly those for C and JS.

That LTE thing, which, surprise surprise, implements a bunch of specs.

He seems to be a God of turning specs into working code, not necessarily a GOd of programming in general.

Yup, but you need to involve yourself deep into quite the diverse range of programming, computer science, math and physics questions to be able to even read the specs, much less implement them. Codecs involve highly arcane math, an emulator not only needs to take care about the CPU but a whole bunch of side chips and associated timings, compilers are an entire field of academic study, and to work with LTE or anything RF in general you need a solid background in RF hardware electrical engineering, RF propagation, antenna theory and god knows what else, just to be able to have a "testbed" that works with your test device but doesn't shut off service to everyone in a few hundred meters around you.

This kind of mental flexibility is what I really admire.

It's just the average thing you learn going through EE or CompE, plus a knack for turning specs to code.

Don't get me wrong, I find him to be an elite dev, but more for the incredible ability to hold a spec in his head in sufficient detail - and do that multiple times.