@@ -971,10 +971,8 @@ of the line containing the header text:
971971
972972 {#identifier .class .class key=value key=value}
973973
974−Although this syntax allows assignment of classes and key/value attributes,
975−only identifiers currently have any affect in the writers (and only in some
976−writers: HTML, LaTeX, ConTeXt, Textile, AsciiDoc). Thus, for example,
977−the following headers will all be assigned the identifier `foo`:
974+Thus, for example, the following headers will all be assigned the identifier
975+`foo`:
978976
979977 # My header {#foo}
980978
@@ -985,6 +983,12 @@ the following headers will all be assigned the identifier `foo`:
985983
986984(This syntax is compatible with [PHP Markdown Extra].)
987985
986+Note that although this syntax allows assignment of classes and key/value
987+attributes, writers generally don't use all of this information. Identifiers,
988+classes, and key/value attributes are used in HTML and HTML-based formats such
989+as EPUB and slidy. Identifiers are used for labels and link anchors in the
990+LaTeX, ConTeXt, Textile, and AsciiDoc writers.
991+
988992Headers with the class `unnumbered` will not be numbered, even if
989993`--number-sections` is specified. A single hyphen (`-`) in an attribute
990994context is equivalent to `.unnumbered`, and preferable in non-English