Unable to control what gets copied to clipboard from a document in QtQuick

There's no hooks in QtQuick's QTextDocument-using items allowing the user to control what gets copied to the clipboard when you trigger a copy; making custom QTextObjectInterfaces useless in QtQuick applications if you want to be able to copy and paste documents containing them in a coherent format, e.g. representing mentions in a chat application as fancy chips while still being able to copy and paste them as plaintext {{@username}}s.