macOS 10.14 appears to be getting an upgraded dark mode and an Apple News app
https://www.techradar.com/news/macos-1014-appears-to-be-getting-an-upgraded-dark-mode-and-an-apple-news-app
Apple's Worldwide Developer Conference (WWDC) for 2018 is about to get underway tomorrow, and that usually means a plethora of updates on software for iPhones, Macs, Apple TVs, and all the other gear Apple makes. It looks like one new macOS feature just leaked out early.
Developer Steve Troughton-Smith spotted that one of the 30-second previews prepared by Apple shows a dark mode for Xcode 10, one of the programming tools available for macOS. The darker Trash icon in the dock suggests that this could be a system-wide feature, though we're going to have to wait until tomorrow to find out for sure.