That’s call binary coded decimal or BCD and that has some advantages ... bits are zero — so the encoding is 0010000101 or 085 hex. If the number had been, say, 905 that would match case ...

By default that’s: Use “h” for hex (default 4 bits), “b” for binary (default 1 bit), “d” for decimal (default 8 bits). Use optional bit length prefix numbers. Use “~” to invert ...