so i've noticed that some particularly obnoxious websites basically fill the dropdown off Firefox's ← button with crap, effectively stopping you from retreating from their website back to the search that got you there.
@noelle@millihertz could also be history.pushState() javascript, which is designed to add useful navigation to single page web apps (like mastodon), but on many websites is used in such a buggy manner that it just breaks history navigation instead