The GitHub Actions workflow first job (foundation) installs the base target of the Docker image. This step installs texlive and on the GitHub Actions ubuntu-latest runners this can take a long time or just fail in general. If this happens, run make test/base-r-notebook to build and test the base-r-notebook image (it could be any image, but this is the smallest). This will cache the base target to the registry and the GitHub Action can skip building it.