Phased light curves of the ExtEEV from four ground-based projects (left) and their frequency spectra after the subtraction of the heartbeat (right). Blue horizontal lines show the 4 × N detection threshold, while the series of vertical solid lines mark the position of consecutive harmonics of the orbital frequency. The pair of thick vertical red lines denote the position of n = 24 and n = 25 TEOs. We note the presence of daily aliases of the n = 25 TEO at ∼0.24 d⁻¹ and ∼1.24 d⁻¹. Phase 0.0 corresponds to BJD 2458373.61518.