https://xkcd.com/2606/ has it figured out.
For some reason ⍼ can’t be in the submission title on lobsters, while it gets fetched successfully via the Fetch button.
The error displayed being Title may not contain graphic codepoints
presumably to disallow emoji titles?
In RTL documents, this is obviously the stock market crash symbol.
I like that it’s similar to the Linking Sigil (LS/Ellis). Since no one knows what the code point is really for, I think it would be keen for font makers to make it actually the Linking Sigil rather than whatever it is now.