Is there a guide to how to use some of the features of HN like the search in the link above?
There is, but I can't remember the link, haha. You just kinda learn things over the years. This one can be reached by clicking on the domain name of a linked article, so it's easy to remember how to get there.
Specifically for search, might as well use hn.algolia.com than figure out how to use HN's hidden(ish) API.
MIT produces interesting engineering content. They've been a regular on the HN frontpage for as long as I've been coming here which is a pretty long time. Why would it be weird?
I suspect it's a chain reaction. Someone (from here) follows one link, then starts clicking around, and finds more interesting stuff, and so on.