by https://www.flickr.com/photos/151015574@N06/, on Flickr

The first one I found on the floor after bleeding the brakes. Then I found another tonight after pulling a wheel off again to work on the suspension. It seemed to fall from the hub area but I can't be sure. They both look brand new, and the only brand new thing I put on recently are wheels (that have only been driven about 30 ft). I'm guessing they aren't important but am curious nonetheless.

edit: no idea why two photos pop up either when I only pasted in 1 link. weird

 

Got no idea either..I know most Mazda parts, but this one leaves me scratching my head.

 

Possible they're springs that hold the plastic wheel center cap in place?

 

What is the diameter of the piece?

 

Without having a size, I can only surmise they are the springs for the centre caps.

I suspect that you or the previous owner have taken off the caps and broken one of the plastic prongs, allowing them to fall out.