Describe the issue
Currently git will show a "Encountered 29 file(s) that should have been pointers, but weren't:" message for "invalid" files.

To prevent this from happening I'd like to add an appropriate check on CI (travis, GHA) that fails, if any file that should be on LFS is actually in the repo.

Could there be something like git lfs check which does what is currently done on git checkout (or whenever the above message would appear) but can be invoked manually, checks for non-pointer files that should be pointers, print those and exit with non-zero if anything was found?