What is loaded volume for Morel MW-266?

35 liters will net you a Qtc around 0.9., so a little "bump" on the lower end before the woofer rolls off.
A standard 0.707 Qtc, is around 87 liters.
The specs on these are not constant in all datasheets i found so.

Fully useable in both 25 and 35 Liters, with a fairly high Q. Just depends what you want as the result.

If no software, this one is quick and easy for box modelling.

https://speakerboxlite.com/subwoofers/morel-mw-266/specifications