The windows tag is a direct child of the tinderbox tag.
<windows>[nested one or more <window> tags]</windows>
The tag takes no attributes and acts as a container for window tags, of which there should always be at least one. The tag covers major views, Info view and text windows. Note that minor view, toolbar and palette states are stored in app preferences, not in the TBX. The same holds for HTML and Nakakoji views.