%x-elements; X - Generated Text/Punctuation Elements

Elements that can be included along with data characters inside the content model of the <x> element.
Declaration
<!ENTITY % x-elements   "| %emphasis.class; | 
                           %inline-display-noalt.class; |
                           %phrase-content.class; | %subsup.class; |
                           %x.class;"                                >
Expanded Declaration

| bold | fixed-case | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | ruby | inline-graphic | inline-media | private-char | named-content | styled-content | sub | sup | x