User:MediaWiki message delivery
This account is controlled by the MassMessage extension. Any user with the "massmessage" user right (list) can send messages via Special:MassMessage which are delivered using this account. Messages may also be sent via Meta-Wiki.
A hidden comment in the wikitext source of the text added indicates who actually sent the message, what wiki they sent it from, and what input list was used.
If you do not wish to receive any messages, add your user talk page to Category:Opted-out of message delivery. You do that by adding the following line (without quotation marks) to anywhere on your talk page: "[[Category:Opted-out of message delivery]]"