Important. Applies to WP icons only (not custom icons).
aria-hidden="true" will hide the element completely to assistive technology. The element will not be in the accessibility tree (kind of like the DOM tree) so a screen reader user will not know the element is there. The aria-label="*" will be ignored because it's hidden.
Additionally, when we add a link without adding a label attribute, the aria attribute returns an empty string (for WP & custom icons).