Left columns 1–4: IRIS spectra of the Mg II k line at 2796.35 Å (a–d), Si IV 1402.77 Å line (f–i), and C II 1330 Å line (j–m) at the four slit positions of raster 89. From left to right: slit positions 1, 2, 3, 4 correspond to spectra 356, 357, 358, 359. The spectra in slit position 1 (column 1) corresponds to the region of the mini-flare at the reconnection site. Right column: SJI 2796 (panel e) and SJI 1330 (panel n) with four green solid vertical lines indicating the four slit positions of the raster. The y-axis unit in the SJIs (e and n) is labelled in pixels on the left and arcsec on the right to show the correspondence between spectra and SJIs.