I suspect it was done old school: Written by Stephen and passed to a LLM to fill in all those links and other garnish and then passed back for final polish by Stephen. That's how I do my write ups (but generally without the LLM bit for shorter efforts).
This is a long write up, and I'm sure it will have been assisted, but in the right way, and not a sloppy way.
I've dropped several commas before conjunctions, soz!