lone option? Docs issue

[Dave Pawson]

https://www.gnupg.org/documentation/manuals/gnupg/Operational-GPG-Commands.html#Operational-GPG-Commands

the --list-sigs option has a statement

" "X" for an eXpired signature (see --ask-cert-expire),"

I can find no documentation for '--ask-certo-expire'
Is this an omission or error?

regards

-- 
Dave Pawson
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