Notifications: text/uri-list must be an array
QQuickDragAttachedPrivate::createMimeData converts a single string or string list (or variant list) into a call to setUrls but it does not do that for a QUrl.
Why this used to work and suddenly didn’t, I don’t know.
I guess this should also be improved on Qt side but for now let’s use the format it expects.
I can drag screenshots from the popup again, and files after a download.