From top to bottom: longitudinal, transverse, and total magnetic field strength inferred from the Fe i 10783 Å inversions. Cutouts from scans 1, 2, and 3 showing internal area of the δ-spot related to the observed changes of the magnetic field are displayed from left to right. The axes in Mm are used in order to allow easier verification of determined parameters listed in the text (e.g., values entering Eq. (1)). The red arrow marks an enhanced patch of transverse magnetic field detected in scan 3 (i.e., during the M-class flare). The black lines represent umbrae of the δ-spot.