Binary package “python3-breathe” in ubuntu focal

Sphinx autodox support for languages with doxygen support (Python 3)

 Breathe provides a bridge between the Sphinx and doxygen documentation
 systems. It enables Sphinx to generate autodoc for languages other than Python
 with the help of doxygen. It also allows one to embed reStructuredText in
 doxygen markup.
 .
 This package provides the module for Python 3.