When an out-of-context (OOC) design flow such as OOC synthesis or hierarchical design is used, the Wizard also uses a special OOC XDC file customized for that instance. The OOC XDC file provides default period constraints on clock ports that would otherwise be constrained by the example design XDC file. This file is managed by the Vivado design tools and can change to reflect core customization changes or core version upgrades. Do not modify this file.