On the other hand: why? Browsers already have a back button that works that way. Users are used to back buttons on the page moving up some in-app hierarchy, which, admittedly maybe they oughtn’t be used to because maybe it’s not a good pattern in the first place.

But instead of reimplementing the browser’s one and potentially confusing the users, why not remove the button entirely and have people use their browser’s more consistent UI? If the extra space is awkward surely there’s something else that can go there.

There are useful cases for history.back, but I’m not sure a back button is it.