A job listing for a Software Development Engineer at Microsoft explains that the Windows platform holder has plans to create a new open source, framework to facilitate game developers to easily build games across multiple platforms, not just Windows and Windows phone, but Android and iOS too (via Neowin).

"New Devices and Gaming" is looking for passionate and experienced developers to join us. Your contribution will have direct impact on how we win back our game developers from our competitors. As a member of the newly formed team, you will have the rare opportunity to influence our planning and design from the beginning. We will create a modern framework that is open source, light-weight, extensible and scalable across various platforms including Windows Store, Windows Phone, iOS and Android. Working on the gaming technologies, you will collaborate with both internal partner teams across the company and external ecosystem partners to enable end-to-end gaming scenarios.

The absence of the word Xbox from any of the language seems to suggest this project is primarily aimed at mobile devices, although the Windows Store does feature on desktop Windows 8 PCs as well as tablet devices.

Neowin notes that Microsoft is not a stranger to open source software, but directly facilitating iOS and Android game development is certainly a new strategy for the firm. Neowin also speculates that we might hear more details about this initiative at GDC 2014, the annual Game Developers Conference being held in San Francisco in a few weeks time.