Along this theme of knowledge, there is the lost art of tuning your page and content sizes such that they fit in as few packets as possible to speed up transmission. The front page of Google for example famously fitted in a single packet (I don't know if that's still the case). There is a brilliant book that used to be a bit of a bible in the world of web sysadmin from the Yahoo Exceptional Performance Team which is less relevant these days but interesting to understand the era.
https://www.oreilly.com/library/view/high-performance-web/97...