The name had actually been predicted in the run up to the launch - the leaked screenshots that turned up on the Apple developer site showed a new wallpaper in the background, which 9to5Mac thought looked like "mountains — or maybe sand dunes... Although, there appears to be a lot of debate around that R - we hear an R, but apparently it's not...
shot at twilight", and therefore would represent the Mojave desert, for for mac OS Mojave. We suggest you listen to this video and tell us what you think.
This particular code would adapt rendering of a website in reaction to Dark Mode settings.
A Dark Mode is nothing new - there has been a sort of dark mode available since El Capitan, but it only changed the appearance of menu bar and Dock.
There was also the Night Shift mode that toned down the colours and removed the blue light that keeps you awake.
The Dock's translucent background becomes darker, the menu bar's drop-down menus are darker (although still translucent). Not all third-party apps offer support for the dark menu bar, and even some Apple apps, such as Safari, currently feature a bright translucent sidebar.
The Dark Mode in Mojave, shown below in the Calendar app, will be applied to all elements of the interface, in every app, system-wide. (We have a tutorial on Using Dark Mode on the Mac here).
In particular, Apple appears to have focused on enhancing the Finder and Quick Look.