Briefly
The document structure role from WAI-ARIA for superscript text. For example, as in mathematical formulas.
The role superscript is assigned to <sup> by default.
How to write it
Assign the tag role. The most suitable for this is <span>. In most cases, it is better to use the tag <sup>.
Elements with the role superscript can have all global ARIA attributes, except for aria and aria.