In the specification, the production of xsl:package's children is defined as:

<!-- Content: ((xsl:use-package | xsl:expose | xsl:global-context-item | xsl:stylesheet | xsl:transform)*) -->

But in the XML Schema for XSL, the definition of xsl:package (http://www.w3.org/2012/07/schema-for-xslt30.xsd#elem_package) does not allow this syntax, it only allows xsl:use-package before xsl:stylesheet, and xsl:expose behind it. It does not allow xsl:global-context-item.