Looks like a fork rebound adjuster to me, if you’ve lost one then give us an e-mail(adress in profile), and i’ll mail it to you or arrange collection if local.Also found an innertube on the trail, but i’m keeping that as whoever left it’s not going to own up to being a litter-lout.

Bump-cos they’re not cheap to replace.

Thought you were going to say “mojo” as it was lost last time I was there in the freeride park and had a bit of a fall……….. 😯