This is a version of Mozilla’s sandstone theme, for the Sphinx documentation engine..
You need to install it locally and configure Sphinx to use it. In your conf.py file:
import mozilla_sphinx_theme
import os
html_theme_path = [os.path.dirname(mozilla_sphinx_theme.__file__)]
html_theme = 'mozilla'
Also, take care and remove the pygments_style configuration, as it may not be of the better taste with the mozilla’s theme.
Enjoy!