LinuxQuestions.org - [SOLVED] brw-rw----+ permissions on /dev/sr0, what is +?

Code:

root@amanda:~# ls -alR /dev/ | grep "+"

brw-rw----+  1 root optical  11,  0 2012-02-17 17:53 sr0

crw-rw----+  1 root video 226,  0 2012-02-17 17:53 card0

crw-rw----+  1 root audio 116,  8 2012-02-17 17:53 controlC0

crw-rw----+  1 root audio 116,  7 2012-02-17 17:53 hwC0D0

crw-rw----+  1 root audio 116,  6 2012-02-17 17:53 hwC0D2

crw-rw----+  1 root audio 116,  4 2012-02-17 17:53 pcmC0D0c

crw-rw----+  1 root audio 116,  3 2012-02-18 09:51 pcmC0D0p

crw-rw----+  1 root audio 116,  2 2012-02-17 17:53 pcmC0D1p

crw-rw----+  1 root audio 116,  5 2012-02-17 17:53 pcmC0D3p

crw-rw----+  1 root audio 116, 33 2012-02-17 17:53 timer

root@amanda:~# stat /dev/sr0 

  File: `/dev/sr0'

  Size: 0                Blocks: 0          IO Block: 4096  block special file

Device: 5h/5d        Inode: 5452        Links: 1    Device type: b,0

Access: (0660/brw-rw----)  Uid: (    0/    root)  Gid: (  93/ optical)

Access: 2012-02-17 17:53:46.534018700 -0500

Modify: 2012-02-17 17:53:46.534018700 -0500

Change: 2012-02-17 19:00:46.651095103 -0500

 Birth: -

So what is the + for? I've never seen that before.

I've looked in man {ls,chmod} and searching for + is useless in the forum search box.