manufacture/mrp_warehouse_calendar/readme/USAGE.md

When a manufacturing order is created out of a procurement evaluation (from an orderpoint, MTO,...) the calendar is considered in the computation of the planned start date of the manufacturing order.

For example, if it takes 1 day to manufacture a product and it is required for Monday, the manufacturing order will be created with planned start date on the previous Friday, if the warehouse operates under a Mo-Fri working calendar.