No, Apple hasn’t introduced a new quiz app. The reason why there’s a question mark in your Mac’s Dock is sadly a lot more mundane than that.
Firstly, let’s be clear what we’re talking about – a question mark such as the one shown in the macOS Dock pictured below:
(I have my Dock pinned to the left of the screen because I’m a proper weirdo.)
If you hover over the question mark icon, you should get a clue as to which program icon has gone missing, in my case Adobe InDesign 2020.
The reason you’re seeing a question mark where the app once lived is likely because the app has been uninstalled or corrupted in some way. If you uninstall apps in Apple’s recommended way (opening the Applications folder and dragging the application in question to the Bin) this shouldn’t happen.
But if programs use their own uninstaller – like Adobe’s Creative Cloud one – that can result in a question mark being left on the Dock in lieu of the icon it expected to be there, if the application was pinned to the Dock in the first place.
It’s very easy to get rid of that question mark. Right click on it, select Options and then Remove From Dock, as shown below.
If you haven’t uninstalled the program in question, the app may have become corrupted. Try reinstalling the application from scratch and that should fix the problem.