When DITA2Go encounters a cross reference, index term, or footnote reference in a context where an <xref> tag would be invalid, the <xref> gets wrapped in a <ph> element. These DITA2Go-generated <ph> wrapper elements need an outputclass attribute. The default outputclass attribute names for cross-reference, index-term, and footnote wrappers are as follows:
[DITAOptions] ; XrefWrapClass = outputclass to use for generated ph elements that ; wrap xrefs where they would otherwise be invalid XrefWrapClass = phxref ; IndexWrapClass = outputclass to use for generated ph elements that ; wrap indexterms where they would otherwise be invalid IndexWrapClass = phindex ; FootnoteWrapClass = outputclass to use for generated ph elements ; that wrap footnotes where they would otherwise be invalid FootnoteWrapClass = phfoot