The default file format is a simple XML document type. The top-level element is <tree>, which contains one or more <node> elements. <node> elements in turn can contain <data> and other <node> elements.

Each <node> element can have two optional attributes:

• type is a text string describing the node type. Currently, Tines supports "todo" and "text" types.
• done is a text string that can take the values "yes" or "no". It is used in conjunction with type="todo" to indicate whether the to-do entry is checked or not.

The DTD is embedded in each hnb file.

<!DOCTYPE tree[
<!ELEMENT tree (node*)>
<!ELEMENT data (#PCDATA)> <!-- (max 4096 bytes long) -->
<!ELEMENT node (data?,node*)>
<!ATTLIST node done (yes|no) #IMPLIED
          type CDATA #IMPLIED
>]>

In addition, the processing instruction <?hnb pos="n" ?> stores which entry was selected when the file was last saved.