New icon for Extension

Notification Sound plays a sound when Firefox shows a notification, since not all notification daemons do that.

I made a very basic icon a few years ago that tried to convey what a “notification sound” is, but it was rather… basic from the beginning.

I’d like to have a much smoother icon and in the process of updating it also have a vector (SVG) version.

I’m very open to what the icon actually contains, but I’d rather stick to something that’s not too abstract. The icon is only used as the add-on icon and never exposed in add-on specific GUI (except for the settings page, where Firefox displays it by default).

Update: Found an icon via https://github.com/opensourcedesign/jobs/pull/303#issuecomment-374780628 :)