I am using `texi2any --epub3 file.texi` to produce an EPUB file from a Texi file.
My Texi file has: - an interior cover image - a title page - menus, chapters, sections - a index It is a Texi file very similar to Bash's texi file. The EPUB file is produced without any errors, and when I check to see if the file is valid (using the `epubcheck` program) I get this 2 errors: ``` $ epubcheck ./my-file.epub Validating using EPUB version 3.3 rules. ERROR(RSC-005): ./my-file.epub/EPUB/my-file.opf(3,58): Error while parsing file: package dcterms:modified meta element must occur exactly once ERROR(RSC-005): ./my-file.epub/EPUB/xhtml/Index.xhtml(90,49): Error while parsing file: value of attribute "border" is invalid; must be equal to "" or "1" Check finished with errors Messages: 0 fatals / 2 errors / 0 warnings / 0 infos EPUBCheck completed ``` So, I have done some digging. :: Zero-th error message The dcterms:modified meta element is MANDATORY in order to create a valid EPUB 3.3 file. It is missing in the current Texinfo EPUB file creation. Here is an code example on how to implement this inside the EPUB file: File: EPUB/my-file.opf ``` ... <metadata xmlns:dc="http://purl.org/dc/elements/1.1/";> <dc:identifier id="texi-uid">texinfo:my-file</dc:identifier> <dc:title>Some title</dc:title> <dc:language>pt</dc:language> <dc:creator>Daniel Cerqueira S.</dc:creator> <meta property="dcterms:modified">2024-08-20T00:00:00Z</meta> </metadata> ... ``` According to: https://www.w3.org/TR/epub-33/#sec-metadata-last-modified :: One-th (first) error message The XHTML's table element, having the border property, is produced in the Texinfo EPUB file creation. But it creates this border property with the value of "0". According to `epubcheck` it should have the value of "" or the value of "1". I have manually changed my EPUB file to have `border=""` and I have noticed that now, my EPUB reader displays the index table, of my EPUB file, properly formatted. Whereas previously, it have a misalignment (which I thought it was normal). My EPUB reader is the KOReader android app. So, here is a code example of how to implement this inside the EPUB file: File: EPUB/xhtml/Index.xhtml ``` ... <table class="cp-entries-printindex" border=""> ... ``` I have not found the spec reference of the XHTML border property (of the table element) online. So I am presuming that what `epubcheck` is saying, it the correct valid way. Final thoughts: I consider this to be a bug, because the EPUB file created by `texi2any` is not according to the specs. If this 2 error messages get addressed, and corrected, it can be said that `texi2any --epub3` creates a valid EPUB 3.3 file (EPUB 3.3 is the most updated version of the EPUB spec, as of today). A suggestion when programming this, is to always use the `epubcheck` program to validate the creation of EPUB (by texi2any), from now onwards.
