backend/ directory is the main place for code that extends JupyterHub for Yandex infrastructure.
infrastructure/ contains various files needed to use JupyterCloud in production (deploy
templates, salt states, etc).
nbextensions/ and labextensions/ contain small and helpful Yandex-only Jupyter extensions.
arcadia_kernel/ contains Jupyter Arcadia Kernel, which can be used in our service.
tools/ contains some small helpful utilities for Jupyter installation admins.