macOS: Python engine is not included. To use plugins, you must install Python 3.x from official python.org.
other Unix'es: Python engine is not included. To use plugins, see instruction inside "default.json" config about "pylib".
For Debian/Ubuntu, you need .deb package, it adds CudaText shortcut to the Applications list, and adds "cudatext" to system path. For others, get .xz package, unpack it to ~/CudaText, and create shortcut by hands.