Evolution detail of brightening events. Panels (a1)–(a8) present the brightening process of Case-21, the event brightens near the loop apex, with multiple loops intersecting and separating during the evolution. Panels (b1)–(b8) show the brightening process of Case-41, as is indicated by the red arrows, bidirectional jet-like features are observed during the brightening process, which may represent key observational signatures of magnetic reconnection between loops.