Templates carry their in-scope xmlns bindings into match patterns
(match cache keyed on pattern plus bindings) and instantiated
expressions, resolving prefixed name tests by namespace URI; with
bindings supplied an unprefixed test selects only the null namespace,
the XPath 1.0 rule. Instruction-scope capture includes the default
declaration: xsl:element honors in-scope xmlns="uri" for unprefixed
names, xmlns="" keeps them namespace-free, and an unusable created
name drops the wrapper, keeping content. Xalan baseline 263 -> 218
(namespace 41 -> 13).