sphinx-external-toc is part of the executablebooks project, who also are responsible for jupyter-book.
We're excited you're here and want to contribute.
The Jupyter Book project is run by a community of people like you, we'd love to have you help out!
Please take a look at the Jupyter Book contributor guide which steps you through the codebase and how to contribute to this project. If you have any questions that aren't answered there, please let us know by [opening an issue][link_issues]!
Thank you for you interest in contributing ✨