ID	Severity	Message	Suggestion
ACC-001	USAGE	'img' or 'area' HTML element has no 'alt' attribute.	
ACC-002	USAGE	'input' HTML element is not referenced by a corresponding label element.	
ACC-003	SUPPRESSED	Non-text html elements should include a 'title' attribute for accessibility.	
ACC-004	SUPPRESSED	Html 'a' element must have text.	
ACC-005	SUPPRESSED	Table heading cells should be identified by 'th' elements for accessibility.	
ACC-006	SUPPRESSED	Tables should include a 'thead' element for accessibility.	
ACC-007	USAGE	Content Documents do not use 'epub:type' attributes for semantic inflection.	
ACC-008	USAGE	Navigation Document has no 'landmarks nav' element.	
ACC-009	WARNING	MathML should either have an alt text attribute or annotation-xml child element.	
ACC-010	SUPPRESSED	Headings should not be used within blockquote and figure elements.	
ACC-011	WARNING	Link elements within SVG should include an xlink:title attribute.	
ACC-012	SUPPRESSED	Table elements should include a caption element.	
ACC-013	USAGE	Content file contains at least one inline style declaration.	Inline styles are not compatible with accessibility settings and display personalization. Use CSS Styles instead.
ACC-014	USAGE	Value of CSS property 'font-size' does not use a relative size.	Acceptable values include percentages, em multiples, 'larger', 'smaller', 'normal' or 'inherit'.
ACC-015	USAGE	Value of CSS property 'line-height' does not use a relative size.	Acceptable values include percentages, numeric multiples, em multiples, 'normal', or 'inherit'.
ACC-016	USAGE	Value of CSS property 'font-size' should use a relative size.	Acceptable values include percentages, em multiples, 'larger', 'smaller', 'normal' or 'inherit'.
ACC-017	USAGE	Value of CSS property 'line-height' does not use a relative size.	Acceptable values include percentages, numeric multiples, em multiples, 'normal', or 'inherit'.
CHK-001	ERROR	The custom message overrides file was not found.	
CHK-002	ERROR	Unrecognized custom message id %1$s encountered in message overrides file '%2$s'.	
CHK-003	ERROR	Unrecognized custom message severity '%1$s' encountered in message overrides file '%2$s'.	
CHK-004	ERROR	The custom message contains too many parameters in message overrides file '%1$s'.	
CHK-005	ERROR	The custom suggestion contains too many parameters in message overrides file '%1$s'.	
CHK-006	ERROR	Unable to parse the custom format parameter in message overrides file '%1$s'.	
CHK-007	ERROR	Error encountered while processing custom message file '%1$s': "%2$s".	
CSS-001	ERROR	The '%1$s' property must not be included in an EPUB Style Sheet.	
CSS-002	ERROR	Empty or NULL reference found.	
CSS-003	ERROR	Only UTF-8 and UTF-16 encodings are allowed, detected %1$s.	
CSS-004	ERROR	Only UTF-8 and UTF-16 encodings are allowed, detected %1$s BOM.	
CSS-005	ERROR	Conflicting alternate style attributes found: %1$s.	
CSS-006	WARNING	CSS position:fixed property should not be used in EPUBs.	
CSS-007	WARNING	Font-face reference %1$s refers to non-standard font type %2$s.	
CSS-008	ERROR	An error occurred while parsing the CSS: %1$s.	
CSS-009	USAGE	Use of certain CSS such as Columns, Transforms, Transitions, box-sizing or KeyFrames can cause pagination issues.	
CSS-010	WARNING	Use of non-standard stylesheet.	
CSS-011	SUPPRESSED	Excessive number of css files.	Consider merging CSS files to reduce the number of CSS files.
CSS-012	USAGE	Document links to multiple CSS files.	
CSS-013	USAGE	CSS property is declared !Important.	
CSS-015	ERROR	Alternate Stylesheet has no title.	
CSS-016	SUPPRESSED	Alternate Stylesheet precedes primary stylesheet.	
CSS-017	WARNING	CSS selector specifies absolute position.	
CSS-019	WARNING	CSS font-face declaration has no attributes.	
CSS-020	USAGE	CSS font selector declaration uses unexpected font-size value '%1$s'.	Acceptable values include percentages, em multiples, 'larger', 'smaller', 'normal' or 'inherit'.
CSS-021	USAGE	Shorthand CSS property 'font-family' specifies an invalid System Font.	Acceptable values include 'caption', 'icon', 'menu', 'message-box', 'small-caption',  'status-bar', or 'inherit'.
CSS-022	USAGE	CSS selector specifies global margin setting.	
CSS-023	USAGE	CSS selector specifies media query.	
CSS-024	USAGE	CSS class Selector is not used.	Remove unused CSS selectors.
CSS-025	USAGE	CSS class Selector could not be found.	Check for typos or define a class selector to document the use of the class.
CSS-027	USAGE	CSS selector specifies absolute position.	
CSS-028	USAGE	Use of Font-face declaration.	
HTM-001	ERROR	Any publication resource that is an XML-based media type must be a valid XML 1.0 document. XML version found: %1$s.	
HTM-002	WARNING	The installed xml parser doesn't support xml version verification. Xml files must be a valid XML 1.0 document.	
HTM-003	ERROR	External entities are not allowed in EPUB v3 documents. External entity declaration found: %1$s.	
HTM-004	ERROR	Irregular DOCTYPE: found '%1$s', expected '%2$s'.	
HTM-005	USAGE	An external reference was found.	
HTM-006	USAGE	An XHTML Named Entity was found.	
HTM-007	WARNING	Empty or whitespace-only value of attribute ssml:ph.	
HTM-008	ERROR	The src attribute is required.	
HTM-009	ERROR	The DOCTYPE provided is obsolete or irregular and can be removed.	
HTM-010	USAGE	Namespace uri '%1$s' was found.	
HTM-011	ERROR	Entity is undeclared.	Define the entity or use the numbered entity instead.
HTM-012	USAGE	Found a link to a CFI in an external book.	
HTM-013	USAGE	Intra-Publication CFIs found in document.	
HTM-014	WARNING	Invalid file extension for HTML file, expecting (html, htm or xhtml).
HTM-014a	WARNING	XHTML Content Document file name '%1$s' should have the extension '.xhtml'.	
HTM-015	WARNING	HTML4 DOCTYPE definition within EPUB v3.	
HTM-016	WARNING	HTML5 DOCTYPE definition within EPUB v2.	
HTM-017	ERROR	Content file has different language value in attributes xml:lang and lang.	
HTM-018	ERROR	Content file has invalid language value at attribute xml:lang.	
HTM-019	ERROR	Content file has invalid language definition at attribute lang.	
HTM-020	USAGE	Content file doesn't contain xml:lang attribute.	
HTM-021	USAGE	Content file doesn't contain lang attribute.	
HTM-022	USAGE	Document may contain excessive DIV or SPAN tags.	Merge DIV or SPAN tags when they are consecutive and use the same style.
HTM-023	WARNING	An invalid XHTML Named Entity was found: '%1$s'.	Check the spelling or use numbered entities instead.
HTM-024	USAGE	An XHTML Named Entity was found. Only '&amp;' '&apos;' '&quote;' '&lt;' or '&gt;' are allowed.	Check the spelling or use numbered entities instead.
HTM-025	WARNING	Non-registered URI scheme type found in href.	
HTM-027	USAGE	List contains less than 2 items.	Lists should have more than one item for accessibility.
HTM-028	USAGE	Input html elements should include an id.	
HTM-029	USAGE	Label html elements should include a 'for' attribute referencing the id of an input element.	
HTM-033	USAGE	HTML 'head' element does not have a 'title' child element.	
HTM-036	SUPPRESSED	IFrames are highly discouraged.	
HTM-038	USAGE	Ensure b, i, em, and strong elements are used in compliance with W3C HTML5 directives.	CSS styles are usually more appropriate for italics or bold text.
HTM-043	USAGE	SVG elements should include an xml:lang and lang attributes.	
HTM-044	USAGE	Namespace uri '%1$s' was included but not used.	Remove unused Namespace URIs.
HTM-045	USAGE	Encountered empty href.	Empty hrefs are valid self-references.  These should be validated to ensure that this is the desired intent.
HTM-046	ERROR	Fixed format item has no viewport defined.	A viewport declaration is required for fixed format items.
HTM-047	ERROR	Html viewport is missing height and/or width.	The viewport declaration must declare both width and height.
HTM-048	ERROR	SVG ViewBox is missing on fixed format document.	A viewBox declaration is required for fixed format documents.
HTM-049	ERROR	Html element does not have an xmlns set to 'http://www.w3.org/1999/xhtml'.	Add xmlns="http://www.w3.org/1999/xhtml" to the html element.
HTM-050	USAGE	Found epub:type="pagebreak" attribute in content document.	
MED-001	ERROR	Video poster must have core media image type.	
MED-002	ERROR	%1$s element doesn't provide fallback.	
MED-003	ERROR	Non-standard image resource of type %1$s found.	
MED-004	ERROR	Image file header may be corrupted.	
MED-005	ERROR	Media Overlay audio reference %1$s to non-standard audio type %2$s found.	
MED_006	USAGE	Some browsers do not support rendering SVG images which use a filename in the xlink:href property.	
NAV-001	ERROR	The nav file is not supported for EPUB v2.	
NAV-002	USAGE	Found epub:type="page-list" in nav document	
NAV-003	ERROR	The Navigation Document must have a page list when content document(s) contain page breaks (epub:type="pagebreak").
NCX-002	ERROR	toc attribute was not found on the spine element.	
NCX-003	USAGE	An .NCX file is required for TOC navigation on EPUB v2 readers.	
NCX-005	USAGE	Found ncx "page-list" in .ncx file	
OPF-001	ERROR	There was an error when parsing the EPUB version: %1$s.	
OPF-002	FATAL	The OPF file '%1$s' was not found in the EPUB.	
OPF-003	WARNING	Item '%1$s' exists in the EPUB, but is not declared in the OPF manifest.	
OPF-004	WARNING	Invalid prefix declaration: leading or trailing whitespace is not allowed.	
OPF-004a	ERROR	Invalid prefix declaration: found empty prefix.	
OPF-004b	ERROR	Invalid prefix '%1$s': must be a valid non-colonized name (aka 'NCName').	
OPF-004c	ERROR	Invalid prefix declaration: prefix '%1$s' must be immediately followed by a colon character (':').	
OPF-004d	ERROR	Invalid prefix declaration: prefix '%1$s' must be separated by its URI with a space.	
OPF-004e	WARNING	Invalid prefix declaration: found illegal whitespace between prefix and URI.	
OPF-004f	WARNING	Invalid prefix declaration: found illegal whitespace between prefix mappings.	
OPF-005	ERROR	Invalid prefix declaration: URI for prefix '%1$s' doesn't exist.	
OPF-006	ERROR	Invalid prefix declaration: URI '%1$s' is not a valid URI.	
OPF-007	WARNING	Re-declaration of reserved prefix '%1$s'.	
OPF-007a	ERROR	Invalid prefix mapping: prefix '_' must not be declared.	
OPF-007b	WARNING	Invalid prefix mapping: default vocabulary '%1$s' must not be re-declared.	
OPF-008	ERROR	Handler binding for core Media-type '%1$s' is not allowed.	
OPF-009	ERROR	The media-type %1$s has already been assigned handler '%2$s'.	
OPF-010	ERROR	Error resolving reference: '%1$s'.	
OPF-011	ERROR	itemref can't have both page-spread-right and page-spread-left properties.	
OPF-012	ERROR	Item property '%1$s' is not defined for media type '%2$s'.	
OPF-013	ERROR	The type property '%1$s' on the object tag does not match the declared media-type '%2$s' in the OPF manifest.	
OPF-014	ERROR	The property '%1$s' should be declared in the OPF file.	
OPF-015	ERROR	The property '%1$s' should not be declared in the OPF file.	
OPF-016	ERROR	The element "rootfile" is missing its required attribute "full-path".	
OPF-017	ERROR	The attribute "full-path" on element "rootfile" must not be empty.	
OPF-018	WARNING	The 'remote-resources' property was declared in the OPF, but no reference to remote resources has been found. Make sure this property is legitimate.	
OPF-019	FATAL	Spine tag was not found in the OPF file.	
OPF-020	SUPPRESSED	Excessive number of spine items.	
OPF-021	WARNING	Use of non-registered URI scheme type in href: '%1$s'.	
OPF-025	ERROR	Property '%1$s' can take only one value.	
OPF-026	ERROR	Found malformed property value: '%1$s'.	
OPF-027	ERROR	Undefined property: '%1$s'.	
OPF-028	ERROR	Undeclared prefix: '%1$s'.	
OPF-029	ERROR	The file '%1$s' does not appear to match the media type %2$s, as specified in the OPF file.	
OPF-030	ERROR	The unique-identifier '%1$s' was not found.	
OPF-031	ERROR	File listed in reference element in guide was not declared in OPF manifest: %1$s.	
OPF-032	ERROR	Guide references '%1$s' which is not a valid 'OPS Content Document'.	
OPF-033	ERROR	The spine contains no linear resources.	
OPF-034	ERROR	The spine contains multiple references to the manifest item with id '%1$s'.	
OPF-035	WARNING	Media type 'text/html' is not appropriate for XHTML/OPS.	Use 'application/xhtml+xml' instead.
OPF-036	USAGE	Video type '%1$s' might not be supported by reading systems 	Use 'video/mp4', 'video/h264' or 'video/webm' instead.
OPF-037	WARNING	Found deprecated media-type '%1$s'.	
OPF-038	WARNING	Media type '%1$s' is not appropriate for an OEBPS 1.2 context; Use 'text/x-oeb1-document' instead.	
OPF-039	WARNING	Media-type '%1$s' is not appropriate in an OEBPS 1.2 context. Use 'text/x-oeb1-css' instead.	
OPF-040	ERROR	Fallback item could not be found.	
OPF-041	ERROR	Fallback-style item could not be found.	
OPF-042	ERROR	'%1$s' is not a permissible spine media-type.	
OPF-043	ERROR	Spine item with non-standard media-type '%1$s' has no fallback.	
OPF-044	ERROR	Spine item with non-standard media-type '%1$s' has a fallback to non-standard media-type.	
OPF-045	ERROR	Encountered circular reference in fallback chain.	
OPF-046	ERROR	Scripted property is not set on mediaType handler.	
OPF-047	USAGE	OPF file is using OEBPS 1.2 syntax allowing backwards compatibility.	
OPF-048	ERROR	Package tag is missing its required unique-identifier attribute and value.	
OPF-049	ERROR	Item id '%1$s' was not found in the manifest.	
OPF-050	ERROR	TOC attribute references resource with non-NCX mime type; 'application/x-dtbncx+xml' is expected.	
OPF-051	SUPPRESSED	Image dimensions exceed recommended size.	
OPF-052	ERROR	Role value '%1$s' is not valid.	
OPF-053	WARNING	Date value '%1$s' does not follow recommended syntax as per http://www.w3.org/TR/NOTE-datetime:%2$s.	
OPF-054	ERROR	Date value '%1$s' is not valid as per http://www.w3.org/TR/NOTE-datetime:%2$s.	
OPF-055	WARNING	%1$s tag is empty.	
OPF-056	WARNING	Media type '%1$s' is not an appropriate audio mimetype.	Use 'audio/mp3', 'audio/mp4' or 'audio/ogg' instead.
OPF-057	SUPPRESSED	Image file length exceeds recommended size.	
OPF-058	USAGE	Spine item has no TOC entry reference.	Every spine item in the manifest should be referenced by at least one TOC entry.
OPF-059	USAGE	Spine item has no NCX entry reference.	Every spine item in the manifest should be referenced by at least one NCX entry.
OPF-060	ERROR	Duplicate entry in the ZIP file: '%1$f'.	
OPF-061	WARNING	Duplicate entry in the ZIP file (after Unicode NFC normalization) '%1$f'.	
OPF-062	USAGE	Found Adobe page-map attribute on spine element in opf file.	
OPF-063	WARNING	Referenced Adobe page-map item '%1$s' was not found in the manifest.	
OPF-064	INFO	OPF declares type '%1$s', validating using profile '%2$s'.	
PKG-001	WARNING	Validating the EPUB against version %1$s but detected version %2$s.	
PKG-003	ERROR	Unable to read EPUB file header.  This is likely a corrupted EPUB file.	
PKG-004	FATAL	Corrupted EPUB ZIP header.	
PKG-005	ERROR	The mimetype file has an extra field of length %1$s. The use of the extra field feature of the ZIP format is not permitted for the mimetype file. 
PKG-006	ERROR	Mimetype file entry is missing or is not the first file in the archive.	
PKG-007	ERROR	Mimetype file should only contain the string 'application/epub+zip' and should not be compressed.	
PKG-008	FATAL	Unable to read file '%1$s'.	
PKG-009	ERROR	File name contains characters that are not allowed in OCF file names: '%1$s'.	
PKG-010	WARNING	Filename contains spaces, therefore URI escaping is necessary. Consider removing spaces from filename.	
PKG-011	ERROR	Filename is not allowed to end with '.'.	
PKG-012	WARNING	File name contains the following non-ascii characters: %1$s. Consider changing the filename.	
PKG-013	ERROR	The EPUB file includes multiple OPS renditions.	
PKG-014	WARNING	The EPUB contains empty directory '%1$s'.	
PKG-015	FATAL	Unable to read EPUB contents: %1$s	
PKG-016	WARNING	Use only lowercase characters for the EPUB file extension for maximum compatibility.	For maximum compatibility, use '.epub'.
PKG-017	WARNING	Uncommon EPUB file extension.	For maximum compatibility, use '.epub'.
PKG-018	FATAL	The EPUB file could not be found.	
PKG-020	ERROR	OPF file '%1$s' could not be found.	
PKG-021	ERROR	Corrupted image file encountered.	
PKG-022	WARNING	Wrong file extension for image. The image is a '%1$s' file but has the file extension '%2$s'.
PKG-023	USAGE	Validating the EPUB against version 2.0, default validation profile will be used.	
RSC-001	ERROR	File '%1$s' could not be found.	
RSC-002	FATAL	Required META-INF/container.xml resource could not be found.	
RSC-003	ERROR	No rootfile tag with media type 'application/oebps-package+xml' was found in the container.	
RSC-004	ERROR	File '%1$s' could not be decrypted.	
RSC-005	ERROR	Error while parsing file '%1$s'.	
RSC-006	ERROR	Remote resource reference not allowed; resource must be placed in the OCF.	Only audio and video remote resources are permitted.
RSC-007	ERROR	Referenced resource could not be found in the EPUB.	
RSC-008	ERROR	Referenced resource is not declared in the OPF manifest.	
RSC-009	ERROR	A fragment identifier should not be used with an img src attribute.	
RSC-010	ERROR	Reference to non-standard resource type found.	
RSC-011	WARNING	Found a reference to a resource that is not a spine item.	
RSC-012	ERROR	Fragment identifier is not defined.	
RSC-013	ERROR	Fragment identifier is used in a reference to a stylesheet resource.	
RSC-014	ERROR	Fragment identifier defines an incompatible resource type.	
RSC-015	ERROR	A fragment identifier is required for svg use tag references.	
RSC-016	FATAL	Fatal Error while parsing file '%1$s'.	
RSC-017	WARNING	Warning while parsing file '%1$s'.	
RSC-018	WARNING	Alternative image file '%1$s' could not be found.	
SCP-001	USAGE	Use of Javascript eval() function in EPUB scripts is a security risk.	
SCP-002	USAGE	Use of XMLHttpRequest in EPUB scripts is a security risk.	
SCP-003	USAGE	Local and Session Storage is not currently supported.	
SCP-004	ERROR	Content file contains script which is not supported in EPUB v2.	
SCP-005	ERROR	Content file contains script but it is not marked as scripted.	
SCP-006	USAGE	Inline scripts found.	
SCP-007	USAGE	Script references 'innerHtml'.	Use a DOM instead.
SCP-008	USAGE	Script references 'innerText'.	Use 'textContent' instead.
SCP-009	USAGE	Content file uses mouse event handlers.	Ensure that all mouse driven functionality is accessible from the keyboard and touch devices.
SCP-010	USAGE	Epub 3 content file contains script.	
