CORS potentially might be worth mentioning to get a beginner familiar with security (why can't I just scrape Facebook cookies from my personal website), yada yada.
I think that's kind of still high level to hold limited attention spans without overwhelming but deep enough to prove that there's a bit more going on beneath the scenes.
I feel most new web developers in those jumpstart "become a programmer in 60 days" classes probably know a bit too much about React and probably not enough about the sockets/IPs/networking serving the static assets. Probably not a requirement on day one, but I bet it might make their first "I have to debug this all the way through the stack" problem less painful.
All hypothetical, at least.