"Heh, heh, that"s a joke, son"

Well, the title of this post is the error message from "Oracle® Database Error Messages: 10g Release 2 (10.2)" document.

PLS-00101: reserved for future use

Cause: This error message is not used yet.(Heh, heh, that"s a joke, son.) Action: none

Although, it has been reserved for future use but somehow it got leaked into Oracle Database 10g documentation. However, this same error is missing from Oracle 11g Database Error Messages. I think its reserved to be used with Oracle 12g, who knows? Has anybody encountered this error ??