Top panel: NICER light curve of ObsID 3020560101 shown at 64 ms resolution in the 1–10 keV energy range. The blue dashed vertical line is the time of FRB 200428. The gray dashed vertical lines delimit the first GTI when the burst forest occurred. The arrow indicates that the count rate is outside the y-axis limit. Middle panel: “zoom-in” view of the burst forest. We detect more than 217 bursts during ∼1120 s. The inset is a zoom-in of the area delimited with a dotted gray box, representing the most intense bursting period. Bottom panel: light curve (with 0.5 s resolution) of the burst forest after eliminating all identified bursts.