Python-scripts (*.py) can be used from BrainVoyager 20. Python is an experimental feature in BrainVoyager 20.0 and official in later versions.
For more information about Python in BrainVoyager, please see Rainer's BV blog. They are an addition to the scripts that are available in the folder /(My) Documents/BrainVoyager/BVExtensions/PythonScripts/ after installation of BrainVoyager.
For the Brain Innovation GitHub page, please see https://github.com/BrainInnovation/ for example for code to create physiological noise regressors.
For Python in BrainVoyager documentation, please see "Python" > "Python Developer Guide" in the BrainVoyager menu, or older documentation is available online at http://fladd.github.io/BVPython/index.html.
For information about the Python language and some useful libraries, see: Python website and the SciPy website. Also, the JavaScript language can still be used in BrainVoyager, and on Mac, AppleScript can be used.