It is amazing that you want to contribute a tutorial case for preCICE!
We welcome contributions and we have a few guidelines and tips that you can follow in the preCICE website.
Note
We use Git LFS to version reference results. These will appear as seemingly empty files containing URLs if you don't have Git LFS installed (optional, mainly useful for our system tests).
We host a Git LFS server for these, which only allows push access under restrictions.
In case you get issues pushing to a fork, set GIT_LFS_SKIP_PUSH=1 or do git push --no-verify.