Why does Thunderbird 45.3.0 display a in e-mails from my town government?
I get the icon in the middle of the monthly e-mails sent from my town hall. I don't remember seeing it in any other e-mails but I may have missed it. I asked the town hall folks (they don't use Thunderbird) and they said they don't see this icon.
Wšykne wótegrona (1)
wild guess, they compose mails using a font that is not installed on your computer. So when it comes to things like fancy quotes that word uses, they are simply rendered in what the computer has. In this case a boxy thing.
This is often seen where folks only use Microsoft products and assume that that is all there is in the rest of the world. It is also seen in legacy mail systems that have failed to move on the the unicode fonts popularized by windows a decade ago.