Best-fit broadband continuum model for the stacked summer 2013 data of NGC 5548 as described in Sect. 6. All the displayed data, labelled in the figure, have been corrected for the emission and absorption effects described in Sect. 4, including obscuration and warm absorption, required for determining the underlying continuum. The soft X-ray emission features seen in the RGS are shown on the continuum model for display purposes. The comt warm Comptonisation component (modelling the soft excess) is shown in black dashed-line, with the power-law (pow) and reflection (refl) components in black dotted-line form. The broadband model spectrum is represented in a solid green line. Residuals of the fit, defined as (data − model)/model, are displayed in the bottom panel.