The software in question is referred to as “App Check,” and by the looks of it, it is exactly there to detect malware. Judging from all the visible evidence (there is nothing official about it yet), the App Check will first scan pre-installed applications to see whether you haven’t already somehow gotten malware on your device.
Secondly, it will of course monitor new installations and warn you if they contain malware.
You can say it’s a malware scanner in the making not just by the name, but also by the accompanying icons with a shield and exclamation marks on triangles. The results of a scan will be “All-good” and “Oh no!”
That’s all great, but let’s underscore the fact that this “App Check” is not yet functional. It probably will arrive in future versions of Android, when it is expected to function along with Google’s “Bouncer” online service.