The jupyeter lab documentation (http://ipywidgets.readthedocs.io/en/stable/user_install.html) asks to run the following command to install labextensions:
jupyter labextension install @jupyter-widgets/jupyterlab-manager
I am working behind a corporate firewall and getting node package manager to work properly is very difficult. Is there some other way to predownload labextensions and then do a local install without the need to use an internet connection?