One of trading methods supposes that in the beginning of the trading day the price sets the borders which will be broken only in one direction. For example, if the price goes above the first five hour highs it means that the price will go up today.
This indicator is intended to work with this method - you can choose when the trading day is started (at 17:00EST aka FXCM trading day, at midnight GMT or at midnight of your local time) and how long to collect the data for "the first part of day".