Not the white team according to report (4)

I believe the answer is:

yolk

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'not the white' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for yolk that I've seen before include "Part of a 7 Down" , "Soldiers go in here" , "Yellow part of an egg" , "Food kept by white" , "Bird food" .)

I've seen this clue in The Times.

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