When WFIGS was unreachable the proxy served its last snapshot, marked stale
(X-Data-Stale, body.stale), with no age limit, and the client source kept
only the rows. The layer then read healthy with a fresh update time and
get_fire_perimeters reported the perimeters as current; three days into an
outage it still said "1 mapped wildfire perimeter in the requested box."
The source now offers getSnapshotDetail ({rows, stale, fetchedAt}); the
layer reports stale with the snapshot's fetch time, the tool adds stale,
retrieved_at and "(data may be stale)", and the proxy serves a stale
snapshot for at most 24 hours, as the GNSS proxy caps its own.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
