What the archive holds, who contributed it, and when the screenshots were taken. Every figure is derived from the published set only.
Bar heights use a square-root scale so quiet months stay visible beside the busy ones; the bands within each bar are in true proportion. Empty months are drawn rather than skipped — a gap in the record is itself part of the record.
First to last screenshot, on a shared timeline ruled by year.
One cell per contributor per year, shaded against the whole grid on a square-root scale so a quiet year stays visible beside 2017. Arrivals, overlaps and departures are the shape to read here; the spans above only say first and last.
How the archive accumulates across the period it covers — the shape of what has been documented, not of when it was collected.