Dtd2html generates a suite of linked html documents listing the components and features of each element in an sgml document type definition (dtd).

dtddiff shows differences between two dtds.

dtdtree shows the hierarchy tree (in ascii) of sgml elements in a dtd.

dtdview is an interactive program for studying an sgml dtd.

stripsgml strips sgml markup from a file, and also attempts to translate entity references to standard ascii characters.