Gives the facts about underpants (6)

I believe the answer is:

briefs

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'underpants' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for briefs that I've seen before include "They are prepared for barristers' perusal" , "CLOTHING" , "Gives information and instructions (to)" , "Documents stating facts and points of law" , "Summaries of legal cases" .)

I've seen this clue in the Sydney Morning Herald.

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