This namespace URI is reserved for the use of the copyall.xsl imported stylesheet and any stylesheets importing that stylesheet. copyall.xsl is used in partnership with an importing stylesheet to tweak the information in data sets.

The importing stylesheet declares specific behaviors by defining template rules for specific nodes in the source tree. The copyall.xsl imported stylesheet will copy all nodes not defined with specific behaviors in the importing stylesheet.

This is documented in the complete publications of the ninth and later editions of Practical Transformation Using XSLT and XPath.