The design envisioned in the filing shows two separate shafts that sit parallelly at the top of the phone and accommodate wireless earbuds, just like how the S Pen goes into Samsung's Galaxy Note series devices.
Going by the patent, the heads of the earbuds, which may come bundled with the device, would be adjustable.
This way, the user will be able to move the heads to point upwards before inserting the buds into the slot or rotate them back to the usual right-angled position suitable for listening - after taking them out of the phone.
In addition to sizing, keeping buds inside the phone may also raise questions around cleanliness as the buds may capture dirt and other particles while being exposed along with the phone.
However, this is not an immediate concern, given that the patent still looks pretty far from reality. Perhaps, Xiaomi would consider this once its earbuds become small enough to fit seamlessly into phones.