The most common and most likely answer to this crossword clue is the 13 letter word PARTICULARISE
I've seen this crossword clue in Independent
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Buddy explains!

The straight part
We know that "Give details of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case give details of = particularise.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PARTICULARISE mean?
PARTICULARISE verb- To make particular, as opposed to general; to restrict to a specific or individual case, class etc.; to single out.
- To be specific about (individual instances); to go into detail (about), to specify.
- To differentiate, make distinct from others.