If you run a automatic to track the progress of your fermentation, a gravity graph will show up. Here's how to read it.
First off: different people use different units. You can set all units used in this graph in your interface settings https://bricks.bierbot.com/#/settings/interface. This includes the unit for the gravity itself °Plato, SG (as as the temperature in °C or °F for the neighbouring graphs).
By default, the graph will display two lines: The gravity (in the unit of your choice) and the fermentation percentage:
While the gravity is straight-forward (well, that's the reading from your Brick) the "% Fermentation" needs a little bit more explanation.
"% Fermentation" is calculated like follows: Suppose you started fermentation with a green beer at SG=1.05 or 12°Plato and are now at SG=1.025 or 6°P. The "fermentation percentage" would be 50% as 50% of the available sugars were already fermented.
If you set the starting sugar after completing your mashing, this value will be used as the maximum. If you didn't set this or started the automatic brew right with the fermentation process, the maximum value of all available gravity readings will be used as a fallback.
Also: You can disable lines in the graph by clicking on the respective item ("Gravity" or "% Fermentation") in the legend below the graph.