`@`0x10
an aura is a finer type on an atom — only a print-label.
0x10 is hexadecimal.
casting to bare @ (the backtick is sugar for ^- @) relabels the same number to print in plain decimal.
glossary
^+ casts a value to the type of another expression, rather than a written-out type.
^+(7 42) is 42, typed like 7.