No, it's not a debugging scenario, sorry to disappoint :)
Here's a recent example I had to deal with: I use a web component that extends the behavior of an input using the keydown event. The author of the web component didn't use jQuery, and set the listener directly on the input element (in the future, the listener might even be in a shadow DOM). Now I want to keep the web component but prevent this keydown handler to run. AFAIK, the only way to prevent this is to set a keydown handler higher up in the tree and
stopPropagation during capture phase.
Using objects as parameters in the event API seems like a good idea, but the API proposed in #12031 isn't very appropriate for this use case. I would use: