Yep, for types that's a new operator. It is also a binary operator for xor, for values. But no unary use from what I remember.They call it "reflection operator" in the paper.

It was previously used by Microsoft for their C++/CLR (or C++/CLI) to mark garbage collected values. But that was after the type, not in front iirc.

To quote the paper - "The reflection operator produces a reflection value from a grammatical construct (its operand)" [0]

[0]: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p29...