Max. Drawdown (Intra-day Peak to Valley)  

Displays the greatest loss drawdown, from the previous highest equity run-up, bar to bar (see Note) looking across all trades, during the specified period. If a new bar equity run-up high occurs, the low equity value is reset  to 0 so that the next maximum drawdown can be calculated from that point.

You can roughly see this value on a detailed equity curve graph by looking from the highest peaks to the lowest peaks moving forward. (Peak to Valley)

 Takes into account commissions (and slippage, if specified for strategies).