XHTML Table Layout
When you insert a table in an XHTML document, an HTML type of table is added. The layout of
an XHTML table includes a colspecs section that allows you
to easily configure some properties. For example, you can change the value of column widths
(width attribute) or the text alignment (align attribute).
Although they appear as part of the Author
mode, the colspecs link and its controls will not appear in your
output. They are just there to make it easier to adjust how the columns of your table are
formatted.
Figure: Table Layout in XHTML Documents