First, I'm no expert and I didn't read the whole thing. The main thing is it was previously sealed, and details the motion regarding the inclusion of assets in the Sept 2008 sale to Barclays Capital. There was some poor dealings with out-going employees of Lehman's, looking to pad their pocket on their move to Barclays and they did some altering of the sale agreement after court approval, and told the board and the court is was an immaterial change with a net wash with assets and liabilities. Thus it was approved without anyone looking at it.
Essentially Lehmans is saying they changed the deal by ~$8B and wants it re-negotiated for fair sale treatment.
So, on the face, this had already been filed with the court, it is just now being made public. I think there is somethings in the document that certainly show unfavorably to Barclays and that was why it was previously sealed. It doesn't change anything, just public now.