I found some Linux files, and when I type ls -lah, it outputs this permissions format:
ls -lah
... drwxr-xr-x. 2 root root ... -rw-rw-r--. 1 roo
From info coreutils 'ls invocation' under Linux
info coreutils 'ls invocation'
GNU `ls' uses a `.' character to indicate a file with an SELinux security context, but no other alternate access method. A file with any other combination of alternate access methods is marked with a `+' character.