Jason Jones, the programmer behind Marathon, Myth and Halo, released a GPL (General Public Licence) version of the source code to Marathon 2, just before Microsoft acquired Bungie last week. Now wags in the open-source community are beginning to call it "Microsoft’s own Open Source initiative".

A General Public Licence is a licence applied to software from the Free Software Foundation, which guarantees users the freedom to share the software and make changes to it. Now, die-hard Mac programmers are using the Marathon source code, and its game engine to create software under the open-source agreement.

Bungie was purchased by Microsoft last week, the company is to become an independent unit based at Microsoft’s Redmond headquarters, focusing on applying its games-engineering skills to creating games for Microsoft’s "Xbox" console.

More information about Marathon Open Source is available from source.bungie.org.