MassMessage to email a couple of years ago sent the username as well as the section header, for example:
MediaWiki message delivery left a message on your talk page. /* Last call for WMF grants feedback! */ new section View message View changes
Currently it only sends an abbreviated form of the username:
MediaWiki message de... left a message on your talk page. View message MediaWiki messa... View changes
I would prefer it to at least include the section header, as this is particularly valuable for event announcements. Really, the bot username can be omitted entirely if we want - perhaps we could set up a special case for MassMessage as opposed to regular talk page messages, as with these usually the subject is more important than the username.