Stores the symbol (such as an asterisk, numeral, or section mark) that was displayed in the original document to identify a specific footnote, if this symbol is to be preserved
For example, it might be useful to store the symbol to disambiguate mis-tagged cases in which an author has stated “see footnote b” or “see footnote 14” in the text, but the “see” note has not been tagged as an <xref> element. When the cross-reference has not been tagged, the normal ID/IDREF connection between footnote and reference is missing, and the only connection between the two is the visually matching symbols (“b” and “14”, respectively).
|Text, numbers, or special characters
|The symbol used to mark a footnote, such as a section symbol
|Restriction: This attribute may be specified if the element is used.