The GMII to RGMII solution delivers files to several file groups. By default, the file groups required for the use of the GMII to RGMII or for opening the IP example design are generated when the core is generated.
The file groups generated are found in the IP Sources tab of the Sources window, where they are listed for each IP in the project. For details, see the Vivado Design Suite User Guide: Designing with IP (UG896).