documentcloud/backbone — pull request #1741 by braddunbar (2012-10-16 12:15:24+00:00)
Title: Add `extend` to Backbone.History.

Using `extend` on `Backbone.History` allows for [cleanly adding functionality such as a `"route-not-found"` event](https://github.com/documentcloud/backbone/issues/308#issuecomment-9482299).