In MoonBot on the spot charts in the upper left hand corner of the chart, I see F-$ and F-B symbols on some coins and none on others. What do they mean?

In the MoonBot terminal, marks appear on some coins on the spot charts in the upper left-hand corner:
F-$ (Futures-Usdt, you will most often see this mark)
F-B (Futures-Busd, you will see this mark less often e.g. on a LUNA coin), which means that this coin is also traded on the futures market on USDT and BUSD.
Why is this important for us to know?
Generally, coins that are also traded on futures markets have larger volumes and are more predictable, because they are harder to manipulate on futures markets, and on the spot market, the price is equalized by exchange arbitrage trading bots and skew movements occur less often than on coins that are not traded on futures.
Also, in some strategies, traders whitelist and trade only coins that are on both the spot and futures markets.