Is the idea that

python_sources

contains the meta data for a group of python files that form a coherent "thing" (now known as a library)? I don't see how changing library to sources reduces the confusion. A python developer still needs to know that another target is needed for making a pex (

pex_binary

) and a wheel/zip (

python_distribution

). Are you trying to create the dichotomy between sources and 3rd party requirements? Requirements come from the

pip

ecosystem. If you are going this route, why wouldn't you also use the name

python_pex

instead of

pex_binary

?