An essential .tcss data file is missing from site-packages when installed into a venv, even though it is included in the source distribution. Project structure is as follows. project/ +---LICENCE.md +---pyproject.toml +---README.md +---requirements.txt +---src/ | +---__init__.py | +---my_module.py | +---my_module.tcss +---git/ Per the setuptools user guide, because the data file is being tracked with git, it should be included in the source distribution and the installation of the package. I have attempted adding a MANIFEST.in file with the appropriate entry, but per the user guide this is actually redundant and made no difference. Is anyone able to shed light on what is required to have the .tcss file installed as expected? Continue reading...