My mom is up there and it is mostly in the Decker Canyon/ south Main Divide area heading down to Lake Elsinore. so mostly on the San Mateo wilderness side. There are several private ranches up in there.
It probably affects the top of South/North Main Divide a bit. There was a trail up by El Cariso fire station that is likely burned over, and probably some of the DH trails coming off Ortega. Fire burned right down the highway hillside.