Question about notations and domains

[Khelben Blackstaff]

On Fri, 09 Aug 2013 09:13:07 +0200
Werner Koch <wk at gnupg.org> wrote:

> If you have a need for a notation key and you can describe the
> purpose, let us know and I may assign one from gnupg.org.
> 

Is there a notation definition for mentioning the procedure followed
for each specific certification ? For example "I met Werner Koch
at the linux convention in Hamburg and verified his passport, then sent
a e-mail challenge, etc".

I have seen 1-2 people using signotes@ but i do not know if it is
widely used or if there is a more appropriate tagname.

Also is there a list or "registry" containing the defined notations ?
The only ones i am aware of are preferred-email-encoding and issuer-fpr.

Thank you again.