The WhatsApp tracker has also spotted a Dark Splash Screen feature. However, the blog notes that this feature hasn't been enabled for beta users yet. The dark welcome screen is most likely a part of the Dark Mode that is currently being tested by WhatsApp.
Other new WhatsApp features you should be excited about
Alongside the much-awaited Dark mode, WhatsApp is also bringing several new features that'll enhance your messaging experience. There are self-disappearing messages that self-destruct after a set period of time, a new Boomerang feature for creating reverse-looped short videos, and the ability to hide muted statuses.