Browser implementers are often wary of providing extension points that can be performance footguns. The biggest footgun is using libraries that rewrite the entire stack in JavaScript, and whole-stack-rewriting strategies are the tactic du jour today. For performance, we have little to lose and much to gain by making extensions more granular.
via Extend the Web Forward « Katz Got Your Tongue?.
This is a good article. But it also taught me the word “footgun”, which is great.