What is the output impedance of the headphone output?

I'm looking to buy a headset to use with the Deluge.
In the official manual (on page 8) I find the following information about the headphone output:
Headphone output
This can drive headphones, or can be used to connect other equipment with a 3.5mm / 1/8” connector - perhaps computer speakers or a car stereo.
But I can't find any info about it's output impedance in ohms.
I did, however, find this info for the right / left-mono line out (also on page 8 of the official manual):
L / MONO and R outputs
The Deluge’s main audio outputs are two quasi-balanced (that is, resistor-balanced but not differential) 1/4" connectors. They will work with non-balanced cables too. For best noise rejection, use balanced cables when connecting the Deluge’s outputs to balanced / differential inputs. Output impedance: 47 ohms.
Does anyone know the output impedance of the headphone out?
Is it the same as for right / left-mono line out, i.e., 47 ohms?
Comments
I have diffrent headphones and they all work just fine.
But [!!!], a higher impedance headphone is usually used in parallel with other headphones, like for background singers. This way (in parallel) the total impedance is lower than just with 1 headphone.
So better use one with lower impedance.
Thanks! I bought Beyerdynamic DT 700 PRO X.