You do not need to have any of the following installed. However, you may find it easier to work with the documentation if you do, and they may give you more flexibility in the output formats that can be generated.
Jade and teTeX are used to convert DocBook documents to DVI, Postscript, and PDF formats. The JadeTeX macros are needed in order to do this.
If you do not intend to convert your documentation to one of these formats (i.e., HTML, plain text, and RTF are sufficient) then you do not need to install JadeTeX and teTeX. This can be a significant space and time saver, as teTeX is over 30MB in size.
Important: If you decide to install JadeTeX and teTeX then you will need to configure teTeX after JadeTeX has been installed. print/jadetex/pkg-message contains detailed instructions explaining what you need to do.
Both these editors include a special mode for editing documents marked up according to an SGML DTD. This mode includes commands to reduce the amount of typing you need, and help reduce the possibility of errors.
You do not need to use them; any text editor can be used to edit marked up documents. You may find they make you more efficient.
If anyone has recommendations for other software that is useful when manipulating
XML documents, please let Documentation Engineering Team <doceng@FreeBSD.org> know, so they
can be added to this list.