EpubCCEPUBCheck HTM-044: unused namespace declared
Updated:
EPUBCheck HTM-044 is a usage message: “Namespace uri "…" was included but not used.” A namespace is declared in a document but never used. It is a usage note: harmless, reported only so you can tidy the markup, and it does not make the EPUB invalid.
The official message
Namespace uri "%1$s" was included but not used.
EPUBCheck's suggestion: Remove unused Namespace URIs.
- Default severity
- Usage. Informative only and hidden by default: it appears when EPUBCheck runs with -u (--usage). It does not make the EPUB invalid.
- EPUBCheck version
- 5.4.0
%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.
Typical causes
- Declarations copied from a template, such as xmlns:svg or xmlns:m on every chapter.
- Markup that used the namespace once and was later removed by an editor.
How to fix it
- Open the file EPUBCheck names (the message gives the path, line and column) in a text or EPUB editor such as Sigil, or unzip the EPUB and open it there.
- Remove the unused xmlns declaration that EPUBCheck names from the html element.
- Keep declarations that other chapters use, such as xmlns:epub, only where they are needed.
- Rebuild the EPUB and run EPUBCheck again to confirm the message is gone.
When it's not this
If the epub prefix points to the wrong URI, that is HTM-010, not HTM-044.
Terms used here
Other HTM messages
HTM-045Encountered empty href.HTM-046Fixed layout document has no "viewport" meta element.HTM-047Viewport metadata "…" has a syntax errorHTM-048SVG Fixed-Layout Documents must have a "viewBox" attribute (on the outermost "svg" element).HTM-051Found Microdata semantic enrichments but no RDFa. EDUPUB recommends using RDFa Lite.HTM_054Custom attribute namespace ("…") must not include the string "…" in its domain.
Sources
Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.