Letters of exclusion
I feel sorry for anyone trying to get into the field of web performance. Not only are there complex browser behaviours to understand, there’s also a veritable alphabet soup of initialisms to memorise. Here’s a really good post on web performance by Harry, but notice how the initialisms multiply like tribbles as the post progresses until we’re talking about using CWV metrics like LCP, FID, and CLS—alongside TTFB and SI—to look at PLPs, PDPs, and SRPs. And fair play to Harry; he expands each initialism the first time he introduces it.