I'd like to propose adding a new processing hint to XEP-0334 to support silent/whisper messages - messages that are delivered normally but don't trigger notifications on the recipient's device.

Use Case:
My mother and I communicate via XMPP throughout the day. She frequently participates in screen recordings and video calls (about 1 hour daily) where notification sounds and popups would be disruptive. However, she doesn't want to use DND mode because she needs to remain reachable for genuine emergencies.
The solution we need: the ability to send non-urgent messages silently so she can read them when she next checks her client, without interrupting her work.