This is a fantastic article! I built something similar a few years ago, except I couldn't rely on a centralized server. So I had to come up with a P2P/decentralized variant of it.
There is a test page up for it, so you can test it out in practice across multiple devices to see how precise (not accurate) it is: https://gunjs.herokuapp.com/game/nts.html
Turns out the math/algorithm isn't too hard! Less than 50LOC for full implementation: https://github.com/amark/gun/blob/master/nts.js
I recommend you have fun and challenge yourself to solve it first before looking at the code! It made me really understand General Relativity spacetime so much more, it clicked.
The idea of riot games posting an engineering article is funny to me. They're famous among their own players for having a very buggy platform, and handling time between framerates is one of the earlier things you learn in game development.
I find it believable but sad that there were apparently eight different implementations of this idea across the codebase. I am not surprised that the developer had to add an ascii skull and crossbones to his code to encourage others not to change it.
Anywhere else I can read this? Blocked at work
As someone who works with clocks that are required to be synced within microseconds, and protocols that keep clocks in sync within tens of nanoseconds, I have to smile about this use of the term high-precision.