A mailbox, consisting of an address (local@domain) and an optional display name.
local@domain
Internationalized addresses (RFC 6532) are allowed; sending them over SMTP requires a server that supports SMTPUTF8.
SMTPUTF8
The local@domain part.
Everything after the last @.
@
True if the address contains non-ASCII characters and therefore needs SMTPUTF8.
Everything before the last @.
The optional display name.
Human readable form, e.g. John Doe <john@example.com>; not encoded for use in headers.
John Doe <john@example.com>