What is the DLL tracker?
Daily loss limit tracking — how close you come to your worst-allowed day, and how often you have gone past it.
Most prop firms fail you for a single day rather than a slow decline, so the daily loss limit is the rule that actually ends accounts. This sub-page tracks your days against that limit.
It is useful even without a funded account. A daily loss limit is the one risk rule that protects you from the compounding part of a bad day — the research the page quotes is that a large single-day loss degrades decision quality for one to three trading days afterwards, so the damage outlasts the money.