What app does macOS Mojave use for screen recording? I just upgraded to macOS Mojave on Macbook Air. I press command + shift + 5 on keyboard, it prompts a window where I select part of screen and then I begin recording my screen. The video quality is good and even the default microphone works well. 

However, it is a little mysterious to me what program it is using for this. In the past, it would use QuickTime. However, I do not see QuickTime or any menu bar visible when this screen sharing utility launches. Also, after I save, and open it, it suggests to open in Quicktime.

Is it using QuickTime behind the scenes, albeit without a menu bar?
If you start screen recording then open the activity monitor.
You will see a process name screencapture.
Click process info botton will see more detail.
It seems like a system level functions and use intel quick sync to encode.