General dropping on unprecedented bulletin (10)
I believe the answer is:
communique
'bulletin' is the definition.
(I've seen this in another clue)
'general dropping on unprecedented' is the wordplay.
I cannot quite understand how this works, but
'unprecedented' could be 'unique' (something unprecedented is unique) and 'unique' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for communique that I've seen before include "Source of news" , "Official statement" , "Official announcement" .)