-as the @code{properties} of the PDF file). For example, setting the
-@code{title} property of the @code{header} block @q{Symphony I} will also give
-this title to the PDF document.
+as the @code{properties} of the PDF file). As metadata are applied per
+output file, only @code{\header} blocks located at top level or within an
+explicit @code{\book} block will be used to generate PDF metadata; while
+@code{\header} variables in a @code{\bookpart} or @code{\score} block
+will be reflected in the printed output of the respective blocks, the
+document-wide PDF metadata will not be affected by headers at that level.
+
+For example, setting the @code{title} property of the @code{header} block
+@q{Symphony I} will also give this title to the PDF document.