The decode-uri() extension pseudo-function “%-decodes” its argument. This argument is assumed to be the string representation of a possibly “%-encoded” URI. For example, decode-uri() can be used to display "D%C3%A9j%C3%A0%C2%20vu.dita", the value of an href attribute, as "Déjà vu.dita".

DITA example:

xref[href]:after {
    content: icon(right-link, 0) decode-uri(attr(href));
}