Package `breathe` - Sphinx plugin for project documentation using Doxygen

[mkoeppe]

https://devblogs.microsoft.com/cppblog/clear-functional-c-documentation-with-sphinx-breathe-doxygen-cmake/

Alternatives: https://github.com/boschglobal/doxysphinx/blob/main/docs/alternatives.md