Jokes that create rifts (6)

I believe the answer is:

cracks

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'jokes' is the definition.

I cannot understand how the rest of the clue works.

(Other definitions for cracks that I've seen before include "'Fractures, splits (6)'" , "Attempts" , "Splits; quips" , "They're how the light gets in, according to Leonard Cohen" .)

I've seen this clue in the Evening Standard.

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