: A bare-bones plugin often used for diagnostic purposes or tools that link against Qt GUI but don't need a full windowing system. Troubleshooting the "No Qt Platform Plugin" Error
This architecture makes Qt cross-platform: same application code runs on Windows, Linux, macOS, and embedded systems by simply loading the appropriate plugin.
ldd /usr/lib/qt5/plugins/platforms/libqxcb.so | grep "not found"