We use QuickJS (the JavaScript runtime he authored) in Minecraft (Bedrock) where even more developers use it to mod Minecraft. It's a huge pyramid of developers!
Checking out Bellard's website is a great high level list of works: https://bellard.org/
The dude can wrap his head around literally anything. Him and Torvalds are truly exceptionally capable people.
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.
This kind of mental flexibility is what I really admire.
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.
Reading that list of projects is quite humbling. I've always wanted to make stuff like that.