Everything together, requirement for final list (2,3)
I believe the answer is:
in all
'everything together' is the definition.
(I've seen this in another clue)
'requirement for final list' is the wordplay.
'requirement for' says the answer is hidden in the clue (the answer is required to spell part of the clue).
'IN ALL' is hidden within 'final list'.
(Other definitions for in all that I've seen before include "Everything considered" , "Altogether" , "totally" , "after considering everything" , "Taken as a whole" .)