Brake Pad Question

I just changed the front brake pads on my 02 Windstar. I noticed when I replaced them though, the old pads had some small little metal nubbers in the back metal shims that go onto the pads. They looked kind of like very small micro sheet metal screws and there were holes in the shims for them to go.

Anyway, the new pads did not come with them and they popped off when I removed the old metal shims. One was even just laying there out of the shim before I removed the first old pad. So I put them new pads on without them and they seem to work fine.

My question is, what are those and what do they do? The brakes seems to work without them.

I looked up brake pads for both my 1996 and your 2002 on the Rockauto website.
Some of the brake pads list a generic picture under "more info"....but looking through a few of them.....your 2002 is different than my '96.
In particular the Monroe Ceramic pads that they list seem to show the most detail of what you get......and shows more detail of the difference between our years.
So.....in short.....I don't know

I understand the anti-rattle clip and the noise reduction shims for the '96.....
And the 2002 version shows the noise reduction shims....but I don't know how the metal clips figure in for the 2002.
A wild guess would be anti-rattle.....but someone with experience with the 1999 and newer can verify what they are for....and how important they are.
My pictures are not going to be much help.......as they are for my '96......and show how everything goes together for that year.