Getting the filename from the Upload component

I would like to know the name of the file a user selects it, in a Upload component that is not
immediate
, but before the user actually starts the upload. Is this possible without extending the client side?

AFAIK, no, you’d need to make modifications to both the client and server sides. You know the file name as the user has started the upload the earliest.
Upload.StartedEvent
has the filename