What does a + mean at the end of the permissions from ls -l?
It means your file has extended permissions called ACLs.
You have to run getfacl <file> to see the full permissions.
See Access Control Lists for more details.
via man page 'ls'
"If the file or directory has extended security information, the permissions field printed by the -l option is followed by a '+' character."
This generally means the file is encumbered with access restrictions outside of the traditional Unix permissions - likely Access Control List (ACL).