I want to send an echo notification to myself. The most obvious and versatile way would be to make this possible using the API, but JS would work for me as well.
My userscript cooks things in the background. If/when it has found something, it has to notify the user somehow. mw.notify is just a fleeting notification that can be missed while taking a sip of one's tea. Other solutions generally don't carry over to other sessions/devices/browsers. And, errr, there already is a perfectly good notification system and area in place, I just can't use it!
Allow userscripts/gadgets/anything that's not an extension to take advantage of echo notifications.
This feature request is different from T58362 as I am requesting only notifications to self (which takes away a whole lot of potential abuse factors) and no special page or user interface, just API.