Android emulator CTRL+S screenshot location
macOS 10, Android Studio 3.1.1
I found it in /Users/<username>/Desktop/Screenshot_1543994371.png
file.
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button in Android emulator menu for Settings\General\Screenshot save location
path.
On Windows 10, Visual Studio, it ends up on the user's Desktop by default.
After a search through device files I finally found it.
/data/local/tmp/screen.png