Canon EOS M6 Mark II Advanced User's Manual page 150

ISO Speed Settings
If a correct exposure cannot be obtained with the maximum ISO speed limit set
z
with [Auto range], a shutter speed slower than the [Min. shutter spd.] will be
set to obtain the standard exposure.
This function will not be applied to flash photography and movie recording.
z
When [Auto(Standard)] is set, the minimum shutter speed will be the
z
reciprocal of the lens focal length. A single step from [Slower] to [Faster] is
equivalent to a single stop of the shutter speed.
150