In-site search is super important. I suspect that many docs maintainers don't realize how heavily it's used. Many docs sites don't even track in-site search queries!
One of the things I love about Sphinx is that it has a decent, client-side, JS-powered offline search. I recently hacked together a workflow for making it search-as-you-type [1]. jasonjmcghee's comment [2] has got me pondering whether we can augment it with transformer.js embeddings.