They're rubbish bins (or perhaps textile recycling bins, but probably not) specifically for national, regional, and/or local flags.
Edited to clarify: No judgment, I am not making a political or societal argument, just posting about a thing I learned exists. If this post gets hijacked I'll ask the mods to lock it.
As an American, I’ve never seen one of these, but many people really believe in honoring the American flag and treating it well, so this isn’t that odd to me
When I was a kid, I was told that you were supposed to burn a flag if it touched the ground so, being a kid and fascinated by fire, I would go to great lengths to make sure flags found their way onto the ground so I could burn them. I would have been immensely disappointed if this had been a thing instead.