Relative source counts with respect to sources having ≥2 G-band FoV transits, illustrating the drop in relative completeness for source sets with ≥12 and ≥20 G-band FoV transits, as applied in our processing (see Fig. 2). Regional values are listed in Table 1 and discussed in Sect. 2.1. Values for external catalogs are Gaia source counts in the approximate sky footprint, not source cross-match counts. Note that actual time series are published only for the 550 K variable sources in DR2 (see Fig. 3).