User Data Stream 'Event Order Update': PARTIALLY_FILLED quantity in event response

For the ‘Order Data’ Stream I am wondering where to get the ‘order quantity’ from the response. So from the API documentation: my understanding is that it’s either ‘q’ or ‘z’ in the payload.

Unless the API documentation for that part is outdated, it doesn’t look like its the ‘original quantity’, since that would be the quantity of the initial order. Can someone confirm its ‘z’ in the response payload?

Example: open 1 order of 1.0 BTC, only 0.1BTC is filled, remaining is 0.9BTC. Where should the information, being filled for 0.1BTC, be found stating that this order has been PARTIALLY_FILLED with 0.1BTC.

I think the doc has made it crystal clear - “z” is “Order Filled Accumulated Quantity”

Okay so in order to get the ‘remainder’ you basically do: q (original quantity) - z (Order filled accumulated quantity)