Traditionally, a banned user will have a large red box that says "User Banned, Please Carry On."
However, in the last couple of days, the behavior has been different.
On mobile (Chrome 91.0.4472.114) I get a broken image symbol.
On desktop (Firefox 89.0), the user's name is repeated as a link.
If I click through to view their full-size avatar, I see the following (in both browsers):
I suspect the original image broke somehow, and the is the Vanilla default... but it doesn't render properly in smaller resolutions, giving the error.