Anything that is not set by your personalization color would be turned dark, such as the background in the Store and Settings apps (see above picture).
Users will be able to enable the feature via a 'dark theme' toggle in Settings. The new feature will be available in the upcoming Anniversary Update - formerly known as Redstone - coming this Summer. A new report from says that yes, the option for a dark theme is coming to Windows 10 for PCs.
If you followed Microsoft's developer conference Build 2016 closely or even today's Edge Web Summit, you might have heard casual mentions of a dark theme in Windows 10.
