Different steps in the pulsation analysis of KIC 3228863, which is one of the stars in our sample. Top: part of the reduced Kepler light curve. Second panel: part of the pulsation light curve, calculated by subtracting the harmonic model from the light curve, with the eclipses and the out-of-eclipse parts shown in grey and black, respectively. Third panel: Lomb-Scargle periodogram of the full pulsation light curve (black), with the pre-whitened frequencies (red). Bottom: Lomb-Scargle periodogram of the out-of-eclipse parts of the pulsation light curve (black), with the pre-whitened frequencies (red).