Hi,

there's a texinfo markup error in matplotlib 1.4.3 and matplotlib 1.5.3:

File doc/users/intro.rst has

Introduction

matplotlib is a library for making 2D plots of arrays in Python <http://www.python.org>. Although it has its origins in emulating
the MATLAB |reg| [*] graphics commands, it is
independent of MATLAB, and can be used in a Pythonic, object oriented
way. Although matplotlib is written primarily in pure Python, it
makes heavy use of NumPy <http://www.numpy.org>_ and other extension
code to provide good performance even for large arrays.

And .. [*] MATLAB is a registered trademark of The MathWorks, Inc.

I guess

MATLAB |reg| [#]_ graphics commands

and

[#] MATLAB is a registered trademark of The MathWorks, Inc.

was meant instead (for auto-numbered footnotes).

See also sphinx-doc/sphinx#3044 for further details.