V4 API does not recognise mushaf query param

[Nurou]

Quran.com seems to be able to switch the mushaf type like so:

The position of words is different depending on the mushaf type. This can be reproduced by setting:
mushaf=5. It calls https://api.qurancdn.com/api/qdc/.

However, V4 (https://api.quran.com/api/v4/) does not recognise the mushaf param. What are the steps for this to get fixed? I can try contribute if needed.