New images hint at a dark mode hidden within macOS Sierra

Upon the release of OS X Yosemite, Apple introduced a feature called Dark Mode that offered a, well, darker look to the dock and menu bar. 

Now it seems that an expansion of the feature could be coming to macOS Sierra. 

As spotted by 9to5Mac, Mac developer Guilherme Rambo posted some screenshots on Twitter showing off an overcast look for Safari and system preferences. 

It’s not clear how Rambo got access to these assets as the feature isn't part of the developer or public beta for macOS Sierra. But its existence suggests that these assets are at least a part of the OS.