This is just an empty repo that is used for testing jupyter notebook code with binder, where the environment is defined in this repo:
https://github.com/pjkohler/binder_main
A binder hub link can then be generated here: https://jupyterhub.github.io/nbgitpuller/link
where binder_main is the environment repo and binder_test (this repo) is the content repo.
Of course, any other repo can also be used as the content repo.