Why does ls show a dot (.) or a plus (+) at the end on the file modes for some files?
-rw-r--r--. 1 root root 1626054 Apr 20 15:44 System.map-22.214.171.124-102.fc11.x86_64
-rw-r--r-- 1 root root 1626169 Apr 24 11:08 System.map-126.96.36.199-111.fc11.x86_64
It is a new feature introduced in the latest version of coreutils included in Fedora 11. The info page on ls (# info ls) has the answer
Following the file mode bits is a single character that specifies
whether an alternate access method such as an access control list
applies to the file. When the character following the file mode
bits is a space, there is no alternate access method. When it is
a printing character, then there is such a method.
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.