Domain Name
resource abstract class.
Mailing list or mailbox information.
Host Information resource.
The email of the person or entity.
Reference: validator.w3.org/feed/docs/rfc4287.html#element.email
Defines a reference to a Web resource. It has the following attributes:
href
rel
type
hreflang
title
length
Reference: validator.w3.org/feed/docs/rfc4287.html#element.link