Alpha Protocol mysteriously taken off Steam "at the request of the publisher" [Updates]

Alpha Protocol, developer Obsidian's 2010 espionage, action-RPG, is mysteriously not for sale on Steam anymore.

Update 2: Sega has now clarified that it still owns the Alpha Protocol IP. The reason for the game's removal has to do with music licensing.

Update: A Sega spokesperson has confirmed to Eurogamer that Sega's publishing rights have expired, meaning developer Obsidian is now in control of the license.

Original story: The product page on Steam now reads:

"At the request of the publisher, Alpha Protocol is no longer available for sale on Steam."

It's uncertain why publisher Sega removed the game from the store. Microsoft purchased Obsidian late last year, but Sega retained the rights to Alpha Protocol. Perhaps Microsoft has struck a deal for IP ownership? Alpha Protocol launched to middling reviews (although it holds very positive user reviews on Steam), and Sega put an indefinite hold on a sequel, but Obsidian told us it was still interested in developing a follow-up. Perhaps Microsoft obtained the rights to the IP, freeing up Obsidian to develop the sequel it always wanted.

Or perhaps, more simply, Alpha Protocol will find a new home at the Epic Games Store, which developers are flocking to since the marketplace takes a smaller cut out of their profits.