[Debian-science-sagemath] ipywidgets: java material

[Jeroen Demeyer]

Indeed. The ipywidgets project (https://github.com/ipython/ipywidgets) 
really contains 2 packages:
* ipywidgets (https://pypi.python.org/pypi/ipywidgets)
* widgetsnbextension (https://pypi.python.org/pypi/widgetsnbextension)

The Javascript stuff is in the widgetsnbextension package. Note also 
that the widgetsnbextension needs to be "enabled" in order to function. 
See the last line of build/pkgs/widgetsnbextension/spkg-install in Sage.