The WG established during its meeting on 17 July 2014 that there was a requirement for a stylesheet author to indicate an intent that all modes used in the stylesheet should be explicitly declared, thus avoiding accidental omission or mis-spelling of "mode" attributes on xsl:template and xsl:apply-templates.

We decided that this intent should be linked to a package, and that the default should be to require explicit mode declarations in an explicit package (but for compatibility reasons, not to require them in an implicit package).

The intent should be signalled by the attribute xsl:package/@declared-modes, type boolean.