According to the definition of "Statically known namespaces,"[1] "Some namespaces are predefined; additional namespaces can be added to the statically known namespaces by namespace declarations in a Prolog and by namespace declaration attributes in direct element constructors."  The description of namespace declarations[2] states that the declaration adds "the (prefix,URI) pair to the statically known namespaces."

The descriptions of schema import[3], module import,[4] and module declaration,[5] however, all indicate that those declarations may bind a namespace prefix and that such a prefix must not conflict with a prefix bound by another schema import, module import, namespace declaration or module declaration.  They do not indicate that the (prefix,URI) pair is added to the statically known namespaces.

I don't see an obvious reason why such a (prefix,URI) pair should not be added to the statically known namespaces - otherwise, the prefix is rendered useless unless overridden by a direct element constructor - so I will assume that this is just an editorial problem.  I suggest the following editorial corrections:

. In section 2.1.1, second bullet, change "by namespace declarations in a Prolog" to "by namespace declarations, schema imports or module imports in a Prolog, by a module declaration,"

. In the last sentence of the first paragraph of 4.2, change "the namespace prefix specified in the module declaration is bound to the module's target namespace" to "the (prefix,URI) pair is added to the set of statically known namespaces."

. At the end of the first paragraph of 4.10 and of 4.11, add the sentence "If it does bind a namespace prefix to the target namespace, the (prefix, URI) pair is added to the set of statically known namespaces."

[1] http://www.w3.org/TR/xquery/#dt-static-namespaces
[2] http://www.w3.org/TR/xquery/#dt-namespace-declaration
[3] http://www.w3.org/TR/xquery/#id-schema-import
[4] http://www.w3.org/TR/xquery/#id-module-import
[5] http://www.w3.org/TR/xquery/#dt-module-declaration