The idea is simple: a bot constantly scans API of main exchanges and sends updates to the channel as soon as sees a new pair. Often developers add a pair on API first and then on their website. And we all know what happens to new currencies on the market. The author constantly adds new exchanges and improves the tool.
The market-maker spread is the difference between the price at which a market maker is willing to buy a security and the price at which it is willing to sell the security. The market-maker spread is the difference between the bid and the ask price posted by the market maker for a security. It represents the potential profit that the market maker can make from this activity, and it's meant to compensate it for the risk of market making. The risk inherent in the market can affect the size of the market-maker spread. High volatility or a lack of liquidity in a given security can increase the size of the market-maker spread.
Be careful.