What is the ATR leading indicator?

Excuse me, I've heard a lot about traders referring to the ATR as a leading indicator, but I'm not entirely sure what it stands for or how it functions. Could you please elaborate on what the ATR leading indicator is? I'm particularly interested in understanding how it's used in cryptocurrency trading, how it helps identify market trends, and what strategies traders typically employ when utilizing this indicator. Additionally, I'd like to know if there are any limitations or caveats to be aware of while using the ATR. Thank you for your time and clarification.