Who leaked the confidential US documents?

Pakistan's double game, Iran's meddling in Afghanistan on the side of Taliban, corruption in Kabul and the high civilian death toll were common knowledge before. So who profited from dropping 91,000 confidential documents in the lap of Wikileaks.org website this week?
Why only classified US military documents? And how does the leak tie in with the undercover Washington-London feud in Barak Obama's term in office?
DEBKA-Net-Weekly digs deep for sources and motivations in its coming issue out Friday, July 30
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