Modelled spectral energy distribution (SED) of a generic PWN with parameters according to baseline model given in Table A.1. See Appendix sectionlinking A.7 for caveats of the SEDs. Left: time evolution of the SED, ranging from 1 kyr to 200 kyr. Right: decomposition of the SED of a middle-aged PWN (10 kyr; black dashed curve) into contributions by leptons from various injection epochs (coloured lines). The grey-shaded bands indicate the energy range of 1–10 TeV explored in this paper.