Per our IRC conversation in MediaWiki-General, I'm re-purposing this bug to be a bit more general that after you send a message, you're given a dead end page.

Some possible places we can link to

• Special:Statistics - will contain number of queued messages for the current site
• Back to Special:MassMessage - some kind of "want to send another message?"
• Special:Contribs/MessengerBot - to track the bot's progress

Probably should just link to all of them.

Dunno where the gerrit bot is... https://gerrit.wikimedia.org/r/#/c/86999/

Change 86999 had a related patch set uploaded by Legoktm:
Add links for the user once the special page has been submitted

https://gerrit.wikimedia.org/r/86999

(In reply to comment #2)

Dunno where the gerrit bot is...

I think there's some stupid rule (read: bug) where the "Bug:" keyword has to be on the line preceding the "Change-Id:" keyword in the commit message.

Change 86999 merged by jenkins-bot:
Add links for the user once the special page has been submitted

https://gerrit.wikimedia.org/r/86999