Frank Terbeck <ft@bewatermyfriend.org> writes:

>   (add-to-list 'org-contacts-new-address-ignore
>                "notifications@github\\.com")

Amusingly I filed a bug with github, saying that they should not emit
mail with a person's name and an email address that does not belong to
the person.  They acknowleged that it would be better not to do this,
but it didn't seem likely to get fixed.

Another useful feature would be to add a property to a person's record
that other names and email addresses shouldn't get picked up.  This
would be sort of like ignoring
  "Fred Foonly <notifications@github.com>"
based on that email address being used in a flaky manner,
and instead ignore
  "Fred Foonly <noreply@massmail.bigcompany.com>"
based on Fred being marked as having odd sending addresses, and
  "Benefits Update <foonly@bigcompany.com>"
based on foonly@bigcompany.com being marked as having odd full-name
parts.