Should trailing periods in the username portion of email addresses be valid?

[josepharhar]

Should an email like this be considered valid? user.@example.com
This was raised here: https://bugs.chromium.org/p/chromium/issues/detail?id=1468257
I see that we have an EBNF and regex here, which I assume allows for trailing periods: https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address
This is the rationale that the chrome bug reporter said:

See https://en.wikipedia.org/wiki/Email_address

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).[7]

Chrome, firefox, and safari all seem to allow these trailing periods.

[smaug----]

See also #1223 and https://lists.w3.org/Archives/Public/public-whatwg-archive/2009Aug/0807.html

[josepharhar]

Thanks! especially for that mailing list link, it looks like trailing periods were intentionally allowed