Sample NICER observation of GRS 1915+105 (ObsID 1103010117). Top left: 1 s lightcurve (0.2–15 keV, not background-subtracted) showing strong erratic variability. Lightcurve gaps (dashed red lines) have been removed for clarity. We also show the hardness ratio (bottom left), here defined as the ratio of the 6–12 keV and 2–4 keV count rates. Right: the corresponding background-subtracted spectrum, rebinned for clarity, with best-fit model (red; an absorbed/scattered disk with emission and absorption lines). The locations of the Fe absorption lines are shown with dotted blue lines; residuals are shown with the absorption line normalizations set to zero. See the text for details.