Pseudo-equivalent width values for Features 1–10 plotted vs. days relative to the epoch of T(B)_max. The measurement symbols are encoded by SN subtype with SNe IIb appearing as blue triangles, SNe Ib as yellow squares, and SNe Ic as magenta squares. Filled shaded regions correspond to the mean ±1-σ standard deviation of a rolling window characterized with a size of ten days. The rolling windows are evaluated on epochs containing at least three distinct pEW measurements and two pEW measurements in the preceding and subsequent epochs.