Frequency and amplitude modulation in the g-mode triplet near 377 μHz. Top-left: fine profile of the triplet in LSP, with near-symmetric frequency spacing. The dashed horizontal line represents the 5.2σ detection threshold. Middle-left: sliding LSP giving a 3D view of the dynamics of the concerning triplet in general. Bottom-left: expanded view of FM around the average frequency (vertical lines, also in the middle-left panel) of each component. Right: measured amplitudes of the three components as a function of time obtained from each piece of light curves. The solid curves are the optimal fitting models of the AM and FM patterns, covering with MCMC uncertainties (see text for details).