/usr/share/doc/libjs-mathjax-doc/html/_static/fonts/Inconsolata-Regular.ttf is in libjs-mathjax-doc 2.7+20171212-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libjs-mathjax-doc/html/_static/fonts/../../../../../sphinx_rtd_theme/static/fonts/Inconsolata-Regular.ttf