This is probably a dumb question, but.. what does "incoming" and "outgoing" mean?

Oh man, don't ask - not a dumb question at all. I'll reshare what I put in another comment that answers it, but bottom line is they're a design gap in the context of /recent.

You're right --- incoming & outgoing end up being redundant on the "Recent" view. Where they're (more) relevant is in the "Top" view where the LLM editor has picked a subset of stories to be categorized as top and incoming/outgoing are the ones that didn't make the cut, organized by timeliness.

Definitely a gap in design!