Lubos Lenco the author behind this is something of a one man army. They also write Armory 3D a game engine that integrates with Blender https://armory3d.org/ ht

Lubos Lenco the author behind this is something of a one man army. They also write Armory 3D a game engine that integrates with Blender https://armory3d.org/ https://armory3d.org/ Fun fact, ArmorPaint is written in haxe which is still a relatively niche language but well worth a look into for building cross-platform apps