What does lifetime after class keyword mean?

I never realized it is allowed to put a lifetime after the class keyword. However, from the LRM,

class_declaration ::= // from A.1.2
[virtual ] class [ lifetime ] class_identifier [ parameter_port_list ]

What does it specify ?

In reply to robert.liu:

That is a documentation bug. Its resolution was missed in 2017. Hopefully it will be resolved in the next version of the standard.

https://accellera.mantishub.io/view.php?id=3561

In reply to sbellock:

Thanks. Got it.