What does the @ symbol mean in a file's permission settings?

I'm on MacOSX, I did ln -s on a directory and these are the results:

-rwxrwxr-x@ 1 shiki  admin   970332 Mar  6 16:38 apc.so
-rwxrwxr-x@ 1 shiki  admin   653884 Mar  6 16:38 eaccelerator.so
-rw-rw-r--@ 1 shiki  admin    60064 Mar  6 16:38 gettext.a
-rwxrwxr-x@ 1 shiki  admin    80320 Mar  6 16:38 gettext.so
-rw-rw-r--@ 1 shiki  admin   514784 Mar  6 16:38 imap.a
-rwxrwxr-x@ 1 shiki  admin  3886132 Mar  6 16:38 imap.so

What do those @ symbols mean?

Solution 1:

@ signifies that the file has extended attributes. Those attributes are usually used to signify that the file came from a package, was downloaded from the internet, etc.

ls -al@ imap.a

will show you the extended attributes that are saved for that file.