The flame tab shows all parameters which apply to the entire flame, rather than just specific xforms. These are the values first encountered in the Xml file before the xform nodes begin.
The tab is broken into tables as a way of grouping relevant fields together.
When the Apply All checkbox at the top is checked, any subsequent adjustment on this tab will be applied to all flames in the currently opened file. However, in order to preserve UI responsiveness, their thumbnails will not be re-rendered to reflect the change. In order to see the change in all flame thumbnails, click the Render Previews toolbar button.