PUBLIC MARKS with tags reactos & "open source"

From the page: "ReactOS® is an advanced free open source operating system providing a ground-up implementation of a Microsoft Windows® XP compatible operating system."

The ReactOS® project is dedicated to making Free Software available to everyone by providing a ground-up implementation of a Microsoft Windows® XP compatible operating system. ReactOS aims to achieve complete binary compatibility with both applications and device drivers meant for NT and XP operating systems, by using a similar architecture and providing a complete and equivalent public interface.