I have the same files on my dev as well. My dev is not set to.allow downloaded apps from unknown sources. And my mob sec won't allow it. But if this is something it missed (unknown dl by 3rd party apps) then they have explaining to do. But every app on dev WAS downloaded from Playstore.That sounds like adware, probably installed by a third party app that you downloaded. The tricky part is finding out which one is the culprit. Have you downloaded any app outside the Play Store?