They're not really 'tricks' as much of mentions of assorted features of HTML and CSS. You get to discover a similar assortment of things (with much more immediately available detail and many examples) just clicking around MDN.
That’s fair, "tricks" may be overselling it. The website is meant to be a small, opinionated collection of features I want to remember, not a replacement for an authoritative reference like MDN. I can probably make that positioning clearer.
Sure, they're not "tricks", but it's also definitely not the same as what you get randomly browsing formal documentation.