VU (Volume Unit) meters are located right above the Volume control sliders throughout the Mixer. The calibration of the VU meters can be changed to suit your preference.
A menu on the left side of Input labels opens a small menu offering three options as follows:
dBVU: Typical analog audio mixers.
dBFS: dB Full Scale, the digital standard. See Configuring Audio.
dBu: Based on a voltage of 0.775 VRMS.