The field plugin:

• Defines which plugins will extract the data from the wiki pages.
• Extends the PageSpec mechanism to allow including conditions related to the values of a given field in a page.
• Extends the SortSpec mechanism to allow sorting according with respect to a given field.

You always need it when dealing with structured data.

The ftemplate plugin lets you use templates that can take the variables they need from the structured data defined in the wiki page they (the templates) are inserted.

The report plugin allows you to generate customized listings of pages. You can define which pages to show, and how to sort them, through the PageSpec and SortSpec standard mechanisms, and you can also define how to present each element of the listing, by defining a template that can use the structured data stored in each page.