.NB File

File extension nb is associated with Mathematica and used for its notebooks.

Notebooks are structured interactive documents that can contain text, graphics, sound, calculations, typeset expressions, and user interface elements.

Mime types:
application/mathematica

Files with nb extension can be typically found as notebook interactive documents made using the Mathematica software.

How to open:

Primarly use Mathematica software to open the .nb files.

How to convert:

Some elements out of .nb documents may possibly be exported and saved in separate files. Maybe images or other visualisations.