All scripts are under the MIT license.
Any lua scripts will require the plugin which is included with HexChat 2.12.1+. These are recommended over the Python versions as they typically have the same functionality but are far lighter on memory and more portable.
Most of the Python scripts will work in Python 2.7 or 3.3+ on Windows or Linux and many require HexChat 2.9.6+ as a lot was changed in that release.
Any javascript scripts will require the plugin I wrote that can be found here.