The wallaby was sighted adjacent to ANBG's Red Centre. It appeared to have an open wound or tumorous area on its right limb which it kept licking, as seen in the second image. Closer inspection of the images appears to show the right limb swollen and with deformed claws. The wallaby was feeding whilst we watched but it and kept licking the wound. The situation was reported to ANBG's Visitor Centre Rangers. Hopefully the animal can be caught and treated. (See follow-up sighting 4682672).
The wallaby looks healthy. It is remarkable how well macropods can cope with injuries, even ones to their hind limbs.
There seems to be a lot going on with that right front limb, including healed injuries and unhealed or new assaults. The bone structure is severely compromised. If the animal was capture-darted, or caught some other way, then taken to a vet, I guess the result would be an amputation, then placement with a wildlife carer for a few months.