Where does the plus sign in file permissions come from?

[Otto Kekäläinen]

Hello,

Listing of ls -la /dev/dvb/adapter0/ shows:
drwxr-xr-x 2 root root 140 2010-03-14 08:20 .
drwxr-xr-x 3 root root 60 2010-03-14 08:20 ..
crw-rw----+ 1 root video 212, 4 2010-03-14 08:20 ca0
crw-rw----+ 1 root video 212, 0 2010-03-14 08:20 demux0
crw-rw----+ 1 root video 212, 1 2010-03-14 08:20 dvr0
crw-rw----+ 1 root video 212, 3 2010-03-14 08:20 frontend0
crw-rw----+ 1 root video 212, 2 2010-03-14 08:20 net0

Where does the +-sign come from? 

As far as I know, Ubuntu does not use ACL by default.

According to "info coreutils 'ls invocation'":

     A file with any other combination of alternate access methods is
     marked with a `+' character.

What is the alternate access method in this case? Something related to
AppArmor or PolicyKit?


I'm trying to debug an issue, which appears in pair with the plus sings
in file permissions. It would be very helpful I somebody could point to
what package makes those attributes..