Classification of the ICL star particles according to the way they were assembled into the ICL. Stellar particles are first classified into in situ and ex situ following Fig. 2, and then ex situ particles are classified into three different categories. On the left: Schematic representation of the different channels, with the main branch depicted in red and a secondary branch in blue. On the right: Mean value of the contribution from each channel for the 324 clusters in THE THREE HUNDRED sample. The top panel is for GADGET-X, the bottom panel for GIZMO-SIMBA.