HistoryReach

How much of an upstream’s history a source can actually reach.

A property of the upstream, not of the source: an RSS feed carrying the last 20 posts cannot be made to yield the 21st by syncing harder. Recorded so the product can say why a backfill stopped where it did, rather than presenting a bounded archive as a complete one.

Properties

Property	Type	Description
kind	"full" | "window" | "recent-only"	full — the whole archive is reachable. window — a bounded window, commonly the most recent N items. recent-only — roughly what is on the front page now.
note	string	Why the bound exists, in a sentence a user could read.