Ibn Ka'b b. Malik reported on the authority of his father that he saw Allah's Messenger (ﷺ) licking his three fingers (after having finished the food). Ibn Hatim made no mention of" three". This hadith is also narrated through another chain of transmitters

Ibn Ka'b b. Malik reported on the authority of his father that the Messenger of Allah (ﷺ) used to eat (food) with three fingers and he licked his hand before wiping it (with towel)

Abdullah b. Ka'b reported that his father Ka'b narrated to him that Allah's Messenger (ﷺ) used to eat with three fingers and when he had finished (eating), he licked them

A hadith like this has been reported on the authority of Ka'b b. Malik through another chain of transmitters