The short version:
“John Riccitiello will retire as President, Chief Executive Officer, Chairman and a member of the Company’s Board of Directors, effective immediately. James M. Whitehurst has been appointed Interim Chief Executive Officer, President and a member of the Board. Roelof Botha, Lead Independent Director of the Unity Board, has been appointed Chairman. Mr. Riccitiello will continue to advise Unity to ensure a smooth transition.”
Tl;dr old CEO made business decision to help bottom line at cost of optics, then old CEO is given the envelope. New CEO steps in, but the bottom line has already been helped, so it’s largely ignored. Corporate speak follows.