Anybody recognize this part?

[Riflebolt]

Hit 14k miles recently on 2015 MK4, built and owned since new. Noticed this part in the driver side foot box floor after a drive. I should remember what it is but it has been too long. Please help me out. Thanks

[CDXXVII]

My Mk4 is earlier than yours and I did not have anything like that.

The only two location that I can think of are.

One of two locking set screws for the steering shaft behind the dash or the locking set screw on the steering shaft to steering rack input shaft.

Neither one of mine were straight blade though.

[txboiler]

Looks like the set screw and locking nut on the steering shaft u joint. I would recommend some blue loctite.

[michael everson]

Locking nut for the brake bias. It goes into the black clevis that the master cylinders are attached to.
Mike

[Riflebolt]

Thanks guys for the responses. I'll use loctite this time. Looking at the assembly, is it true this set screw is redundant? There is a jam nut on the end of the threaded rod (attached).Wilwood master cylinder bias.jpg