multiple underscores in email addresses

[rdk01]

Hello,

The registry does not allow email addresses that start with multiple underscores ('_').
Example: __user@domain.com

According to RFC 5322, such email addresses are completely valid.

https://datatracker.ietf.org/doc/html/rfc5322#section-3.2.3

[vohmar]

local-part of an email address supports following characters according to RFC5322:

• uppercase and lowercase letters A to Z and a to z
• digits 0 to 9
• dot ., provided that it is not the first or last character and provided also that it does not appear consecutively (e.g., John..Doe@example.com is not allowed)
• special characters: !#$%&'*+-/=?^_`{|}~