Anyone recognize this fastener?

[Tyler]

Found it on my driveway. Its a very coarse thread T30 Torx fastener with round head and captive washer. I don't recall running across many Torx fasteners on my E9 but it looks about 40 years old and I get nervous when I find these sort of things near my car!

 

[Stevehose]

Looks more like it came off your Bronco

I dont recognize such a screw for e9 unless a PO put it on.