Presumably they want to at least hold a portfolio of strategic patents.
Royalties, most likely. Discounts on cars in exchange for licenses. Maybe something to auction off during the bankruptcy process so that investors get a fraction of their money back.
Patents can be the most valuable thing a company has. Google pretty much wound up scooping the patents out of Motorola and selling the rest (you know, the thousands of smart people and hardware and history) for a discount.
http://www.wsj.com/articles/ford-says-it-will-focus-more-on-...