Re: what is this
I agree with cheapjeep, I've never seen something like that ever either, and they're definitely not mudflaps. If anything, they may be some sort of mudflap support bracket.
2001 Silverstone Metallic WJ Limited:
Gen III Clear/Chrome Projector/CCFL Halos/LEDs, 8K HIDs, 8K HID Projector/Halo fogs, Clear/Chrome Tail Lights and 3rd Brake Light with LEDS, Diamond Mesh Upper and Lower Fascia, Spectre CAI, Breather Filter, Cabin Air Filter, Low-Temp Thermostat, Jet Stage 1 Chip, MagnaFlow Exhaust with Resonator Tip, Shorty Antenna, Front/Back De-badged