R2 Control Panel Indicators

I’m trying to understand the readouts on the R2 LED during roasting.

Specifically, there’s a single LED dot that sometimes appears below the secondary/ROR digital display in the upper left quadrant. What is it?

UPDATE: I think I found it in the manual after all. Sounds like what I’m asking about is called the “XLED light”:

Bullets with the IBTS Module will by default show the IBTS temperature as the Bean
Temp. The XLED light above the A button will be ON when the temperature is from the
IBTS and OFF when displaying the bean probe temperature. By pressing the A button
you can toggle between the bean probe and the IBTS.

My guess is that cycling through the different data sources for this display gives you maybe, BT ROR, IBTS ROR, instant power, …something else?

Is there a general guide to the control panel and its readouts for the R2? I didn’t see this information in the user manual.

I will post a screen recording next time I roast.