Which software is based on the Python programming language for defining system functionality?

Global Scripter is the correct answer as it is specifically designed to leverage the capabilities of the Python programming language to define system functionality in Extron's AV systems. This software allows users to create complex automation scripts and interactions using a familiar programming language, making it more accessible for those already knowledgeable in Python. Global Scripter provides an effective means for controlling various AV components, enabling integrators to tailor functionality and streamline operations in sophisticated AV setups. It enhances flexibility and user control, allowing the development of custom applications that interact with Extron's hardware seamlessly.

Other software options, while they may offer scripting capabilities or integration with Extron systems, do not utilize Python in the same manner or are not primarily focused on the extensive functionality that Global Scripter provides.