Campfires and their relation to the magnetic field. Panel a: synthetic EUI 174 Å image of a small field-of-view around a transient brightening close to its maximum intensity (the time given in the panel label; see also light curves in Fig. B.1). The x and y directions are marked and a bar indicates a scale of 1 Mm. The intensity scale is logarithmic. Panel b: vertical magnetic field in the photosphere in the same field of view and at the same time as in panel a. The magnetogram is saturated at ±350 G. In purple we show a mask of the bright EUV emission in panel a. The differently colored lines show field lines that pass through the volume of the transient brightening (cf. Sect. 3.3). Panels c–d and e–f: same thing as panels a–b, just for different campfires. These three examples represent the groups (i) to (iii) defined in Sect. 3.3. More examples are shown in the same format in Figs. 5 and A.1. Animations for these three cases are available online. See Sect. 3.3.