InvalidXLogRecPtr in docs

I found a term "InvalidXLogRecPtr" in 9.0 docs.
http://developer.postgresql.org/pgdocs/postgres/functions-admin.html#FUNCTIONS-RECOVERY-INFO-TABLE
| ... then the return value will be InvalidXLogRecPtr (0/0). 

I think it should not appear in docs because it's a name for an internal
constant variable. I'd like to rewrite the description like:

... then the return value will be 0/0, that is never used in normal cases.

Comments?

Regards,
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Takahiro Itagaki
NTT Open Source Software Center