Add comment on tarball and project name

Co-authored-by: Bob Dröge <b.e.droge@rug.nl>

Author: Neves-P

scripts/ingest-tarball.sh

@@ -261,6 +261,7 @@ tar_top_level_dir=$(echo "${tar_first_file}" | cut -d/ -f1)
 # Handle longer prefix with project name in dev.eessi.io and
 # get the right basedir from the tarball name
 if [ "${cvmfs_repo}" = "dev.eessi.io" ]; then
+    # the project name is the second to last field in the filename (e.g. eessi-2023.06-software-linux-x86_64-amd-zen4-myproject-1744725142.tar.gz)
     project_name=$(echo "${tar_file_basename}" | rev | cut -d- -f2 | rev)
     basedir="${project_name}"/versions
 else