Which app has a notification icon of a chat bubble with the letters XL inside it?

[AC Question]

The phone is Sony Xperia, I saw in a screen shot a notification icon in the status bar that looks like a chat bubble with the letters XL inside it. Does anyone know which app this notification icon belongs to?

 

[Flitter420]

Sorry, I don't know what notification that is but I am also curious as to what shows up as mobile communicator on the lock screen of a Note 3. It's a backwards chat bubble with an x in it.