An IDREF-type attribute that points to the Identifier attribute of the <glyph-data> character inside a <private-char> element. The idea is to use the full <glyph-data> with its name and bitmap once, then point to an existing character instead of defining the entire <glyph-data> element repeatedly.
| Value | Meaning |
|---|---|
| An identifier (IDREF) | The pointing uses the ID/IDREF mechanism, using the @glyph-data attribute of the <glyph-ref> element to point to the @id attribute of an existing <glyph-data> element. |