@chris In other words, the Android app that Stenzek releases, is illegal and could be removed from the Google App store. This is because, for the Android version of DuckStation, Stenzek is withholding the source code even though most of the code in duckstation.git does not belong to him, and was provided under GPLv3 - so, not providing source is copyright infringement.
Someone should report the Android app. A fork is needed; SwanStation for example is a fork of DuckStation and part of libretro.