The Xbox app on Windows 10 just got a bunch of new functionality, and some of it's actually pretty interesting (if not exactly something you haven't seen elsewhere already). The big addition is that of the Xbox app's Game DVR for PC games, allowing up to record clips of games being played through Windows.
Once the update arrives, those on Windows 10 will be able to record clips of their most recent 30 seconds of play, or start and stop recording manually as they see fit. There's a few options for length and audio/visual quality of recordings, but generally it's a pretty straightforward addition that might prove very useful. I would hope it isn't a performance hog to record as you play. That seems to be the case with some grabbing software, though this is Windows, so you never know.
Other additions include screenshots, which requires you to press Windows + Alt + PrtScr at the same time, rather than Steam's F12 or FRAPS' whatever key you want it to be. Hopefully that will be customisable.
More details are available on the Xbox Newswire.