[Doitsu]

I attached a test case that illustrates several isuses that I found when checking older commercial epub3 books with epubveri. In most cases EPUBCheck produced more helpful messages.

epubveri reported:

Spoiler:

USAGE OPF-088: epub:type value 'sidebar' is not in the default vocabulary [OEBPS/Text/Section0001.xhtml:13:3]
USAGE OPF-086b: epub:type value 'sidebar' is deprecated [OEBPS/Text/Section0001.xhtml:13:3]
USAGE OPF-088: epub:type value 'note' is not in the default vocabulary [OEBPS/Text/Section0001.xhtml:15:3]
USAGE OPF-086b: epub:type value 'note' is deprecated [OEBPS/Text/Section0001.xhtml:15:3]
USAGE OPF-086b: epub:type value 'warning' is deprecated [OEBPS/Text/Section0001.xhtml:17:3]
USAGE OPF-087: epub:type value 'list' only restates the semantic of its host element "ol" [OEBPS/Text/nav.xhtml:14:5]
USAGE CSS-029: well-known media-overlay class '-epub-media-overlay-active' is used but not declared in the package metadata [OEBPS/Text/Section0001.xhtml]
INFO CSS-007: font '../Fonts/Charis-Bold.ttf' is a foreign resource, exempt from requiring a fallback [OEBPS/Styles/font.css]
INFO CSS-007: font '../Fonts/Charis-BoldItalic.ttf' is a foreign resource, exempt from requiring a fallback [OEBPS/Styles/font.css]

EPUBCheck reported:

Spoiler:

USAGE(OPF-086b): OEBPS/Text/Section0001.xhtml(13,26): epub:type value "sidebar" is deprecated. Consider using a bare "aside" element instead.
USAGE(OPF-086b): OEBPS/Text/Section0001.xhtml(15,23): epub:type value "note" is deprecated. Consider using a "footnote" or "endnote" property instead.
USAGE(OPF-086b): OEBPS/Text/Section0001.xhtml(17,26): epub:type value "warning" is deprecated. Consider using the "notice" property instead.
USAGE(CSS-028): OEBPS/Styles/font.css(2,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(3,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(4,3): Use of Font-face declaration.
INFO(CSS-007): OEBPS/Styles/font.css(5,3): Font-face reference OEBPS/Fonts/Charis-Bold.ttf" refers to non-standard font type "application/x-font-opentype".
USAGE(CSS-028): OEBPS/Styles/font.css(5,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(9,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(10,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(11,3): Use of Font-face declaration.
INFO(CSS-007): OEBPS/Styles/font.css(12,3): Font-face reference OEBPS/Fonts/Charis-BoldItalic.ttf" refers to non-standard font type "application/x-font-opentype".
USAGE(CSS-028): OEBPS/Styles/font.css(12,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(16,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(17,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(18,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(19,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(23,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(24,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(25,3): Use of Font-face declaration.
USAGE(CSS-028): OEBPS/Styles/font.css(26,3): Use of Font-face declaration.
USAGE(CSS-029): OEBPS/Styles/font.css(33,1): Found CSS class name "-epub-media-overlay-active" but no "media:active-class" property was declared in the package document.
USAGE(OPF-087): OEBPS/Text/nav.xhtml(14,26): epub:type value "list" is not allowed on documents of type "application/xhtml+xml".

Both epubveri and EPUbCheck didn't like the epub:type="list" attribute in the NAV TOC but gave different reasons. EPUBCheck offered alternatives for deprecated epub:type attributes.
Somehow fonts with a application/x-font-opentype MIME type triggered "font 'XXX' is a foreign resource, exempt from requiring a fallback" messages.