Game streaming services are gaining steam as viable alternatives to spending big money on decked out PCs and dedicated gaming consoles, and they've come a long way in a relatively short time. One of the benefits is they're mostly platform agnostic. Or they should be—there are multiple reports that Microsoft's Xbox Cloud Gaming service looks noticeably worse on Linux systems than it does on Windows.
This was brought to attention on Reddit where Spiritual-Ad2806 said they noticed that the image quality appeared lower in Ubuntu and Manjaor compared to Windows. Suspecting they weren't just imagining things, they decided to alter the browser user agent strings to spoof running Linux on the same PC.
According to Cohen, the Xbox Cloud Gaming team is “working to improve support and access for a wider range of devices and operating systems” and is “considering changing defaults to be smarter.” While that’s far from an official announcement, it does sound like Linux / Xbox gamers may want to keep an eye out. For now, though, the user agent trick seems to work just fine if you want to get the most out of your Xbox Game Pass Ultimate subscription.