How to report Code Coverage metrics across git repositories?
If you use python and GitLab like I do, you can include a test coverage report in your CI/CD pipeline. You pip install coverage and then just run coverage in your pipeline. The following is an excerpt from an AWS lambda pipeline, but you should be able to find something similar for your environment:

 script:
    - pip install -r ./awslambda/requirements.txt
    - coverage run -m unittest discover -v -s "./awslambda" -p "*_test.py"
    - coverage report


The above generates a nice code coverage report and it is free of charge, for Python, AWS and GitLab.