Panels 1–7: sliding FT of K 1−16 centered on the peaks at ∼229.7, ∼471.7, ∼498.7, ∼541.6, ∼569.0, ∼581.3, and ∼663.0 μHz. The color-coded amplitudes are given in σ units, i.e., amplitude divided by the mean noise of each FT. The oscillations are not stable over the course of the TESS observations, and in the first ≈200 days (up to Sector 22) some of the modes are absent. Panel 8: sliding WF obtained using a single sinusoid of constant frequency and constant amplitude of one, without any noise. The frequency scale is the same in all panels. See text for more details on sFT and sWF computations.