A new Windows 10 Insider Preview is live in the Dev channel, as is typically the case on a Wednesday morning at 10am PT. And as usual, there's not much that's new. The build number is 20236, and there's one key new feature: you can change the refresh rate of your display.
High refresh rate screens are popular with gamers, and you can buy gaming PCs with up to a 360Hz refresh rate. But while screens with higher than 60Hz refresh rate have been sold for years, you've never been able to control it in Settings. One app you can use is Nvidia Control Panel, something that likely comes pre-installed if you have an Nvidia GPU, but this is really about merging more of Control Panel into Settings.
But starting with build 20236, the feature is built right into Settings. You just have to go to Settings -> System -> Display -> Advanced display settings.
As usual, you can grab today's build through Windows Update. If you're not on the Dev channel just yet, you can enroll by using the Windows Insider Program tab in Settings.
Update: Updated to reflect that this was already available in Windows.