Concluding part (6)
'concluding part' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for finale that I've seen before include "Last part of something" , "Denouement" , "Final section of a musical composition" , "Ending" , "Last item of event" .)
(Another definition for tailend that I've seen is " Charlie, sort of".)