Ezio Melotti added the comment: Sphinx is configured to use Python3Lexer (highlight_language is set to 'python3' in Doc/conf.py). 'nonlocal' is not highlighted because in the pygments version that we are using 'nonlocal' is missing in Python3Lexer.tokens['keywords'] see (Doc/tools/pygments/lexers/agile.py:196). If this is fixed in more recent pygments versions, we only have to update our version. ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue13801> _______________________________________