What can wonky APIs tell us about the web?

A few days ago, Misty posted something that caught my eye: Misty @misty@digipres.club Finding myself asking if there's ever been a wonkier official browser API than canPlayType 18 Jun 2026 at 17:52 The HTMLMediaElement.canPlayType API tells you how likely it is that a browser can play media with a given MIME type, but the response is unusual. The word “likely” is important here, because it’s not a simple yes/no answer. The possible responses are: "" – no, the browser can’t play the media "probably" – the browser can probably play the media "maybe" – there isn’t enough information to determine if the media is playable. A ternary, probabilistic response is already a bit weird; the return values double down on the weirdness. A clearer set of return values would be "no", "probably" and "unknown". But when thinking of wonky web APIs, my mind went somewhere else: to History.pushState() and replaceState(). These APIs are for manipulating your browser history, and take an unused parameter…