Shipping the frontend for features in a core product area on a large team, just like a lot of other devs here :)

To go into specifics of actual problems solved and do so intelligibly, I'd have to provide specific context, which I'm not comfortable doing here.

It's a lot easier to describe "interesting problems solved" using less identifiable (and more generally interesting) details if one is in platform/infra and/or operating at a Staff+ level -- both of which I have been in the past (and loved it), but am not at the moment.