Modelling of transit photometry and RVs of TOI-4860. Top panel: ExTrA transit photometry observations of TOI-4860 b. Each column corresponds to a night (labelled with format YYYY-MM-DD) and each line to an ExTrA telescope (labelled T1, T2, and T3) that is offset vertically for clarity. For each transit, the median model (black line) and the 68% CI (grey band, barely visible) computed from 1000 random posterior samples are shown. Middle panel: TESS (separated by sector) and ExTrA transits detrended with the MAP model (whose transit component is shown as a grey line) and phase-folded. TESS sector 10 looks more V-shaped due to the 30-min sampling. Bottom-left panel: SPIRou RVs (red error bars), median model (black line), and 68% CI (grey band). Residuals from the median model are shown. Bottom-right panel: same as the bottom-left panel but for ESPRESSO RVs (blue error bars). The time span of the ESPRESSO panel is highlighted as a blue band in the SPIRou panel.