pip supports VCS installs, as documented in https://pip.pypa.io/en/stable/topics/vcs-support/ (related question: How can I install from a git subdirectory with pip?).
However, it seems that it’s not possible to install providing the extras, i.e. the optional dependencies (as in https://setuptools.pypa.io/en/latest/userguide/dependency_management.html#optional-dependencies). Is this right? Is there any workaround?