Valve appears to be working on a set of "compatibility tools," called Steam Play, that would allow at least some Windows-based titles to run on Linux-based SteamOS systems.

Yesterday, Reddit users noticed that Steam's GUI files (as captured by SteamDB's Steam Tracker) include a hidden section with unused text related to the unannounced Steam Play system. According to that text, "Steam Play will automatically install compatibility tools that allow you to play games from your library that were built for other operating systems."

Other unused text in the that GUI file suggests Steam Play will offer official compatibility with "supported tiles" while also letting users test compatibility for "games in your library that have not been verified with a supported compatibility tool." That latter use comes with a warning that "this may not work as expected, and can cause issues with your games, including crashes and breaking save games."

Tools that let users run Windows apps in Linux are nothing new; Wine has existed for decades, after all. But an "official" Steam-based compatibility tool, with the resources and backing of Valve behind it, could have a huge impact on the Linux development space that could reach well beyond games. Assuming it worked for a wide range of titles, the Steam Play system could also help ameliorate one of SteamOS' biggest failings—namely, the relative lack of compatible games when compared to Windows.

With all that said, some caution is warranted before getting too excited about these possibilities. For one, we don't know what specific form Steam Play will take. Valve could simply be preparing a wrapper that lets users run existing emulation tools like Wine and DOSBox on top of SteamOS without actively advancing the state of that emulation directly. (Valve has not responded to a request for comment from Ars Technica).

The timing of any such move by Valve is also an open question: SteamDB shows work on the compatibility tools and a related package of "Valve Compatibility Manifests for Beta Testing" has been ongoing since at least since December. Given the schedule-warping vagaries of Valve Time, it could be a while before Steam Play becomes a thing we can actually use—if it ever happens.

Remember, too, that games running on SteamOS already tend to take a performance hit compared to those same games running on the same hardware under Windows. Adding another "compatibility tool" to the mix could easily exacerbate those problems, though wider adoption of the open source Vulkan graphic standard might help cancel out such issues.

Valve said as recently as April that it is "still working hard" on SteamOS and that the company has "other Linux initiatives in the pipe that we're not quite ready to talk about yet." Improved and/or streamlined Windows game compatibility through Linux would definitely be a concrete sign that the company still cares about an OS that has appeared to be all but dead for a while now