what is user @SYSTEM?

[Debian Flo]

>>
>> I am going through the conf files. And there is this user @SYSTEM.
>>
>> I can't find what it is exactly. My search hasn't been successful til now.
>>
> 
> @SYSTEM specifies any user which is a member of the system group, i.e. a 
> user which has administrative rights.
> 

Thanks for your answer.

Is that group on a GNU/Linux system the 'sys' group or the 'lpadmin'
group? Or in other words: a system wide system group or only in the
scope of CUPS?

Regards,
Flo.