Metal Pavers / bricks for drainage?

I’m looking for something like this. Individual pavers made of metal that allow drainage.

I have Googled repeatedly but not seen anything really close. These are on a city sidewalk.

I can’t tell if they just drain onto the ground (paver dust, or whatever the underlying prep was) or if there is some sort of drainage system below.

Anyone know where/how to buy these? Or what they might be called? I’ve been Googling “metal pavers”, and “metal bricks”, and “bricks for drainage” and similar.

This is in Boston, not far from Quincy Market. There was a storm drain nearby, but Boston also tries to keep groundwater in the ground. I assume that’s what’s going on here but I’m not positive.

Also, I’m not here often so I haven’t seen how they do in a heavy rain. (Not to mention they’re all dunked up from apparent lack of maintenance)

Thank you.