What do the two green arrows on the top center-left of the dashboard signify?

How accurate are the battery levels in the upper right corner?

Is there a list somewhere of the different Sensors and what they are telling you?

In my Standard Dashboard for my Xmaxx I have "Voltage" (source: receiver or ESC) the iconography says "Battery" But it sits at 5.8 to 6 all the time. It doesn't matter if I have a full or empty set of 4s 6700 or 2s 5800. Just wondering what that 6 means.

Anyways I know I'm a noob at this, just trying to get an idea of all areas of my new Xmaxx