[tex4ht] tex4ebook EPUB file has an empty title

[Daniel Cerqueira]

Hi.

I am using tex4ebook to try to create a file that comply to the EPUB 3
standard. I have a .tex file.

I successfully create the EPUB 3 file, using my .tex file, through the
tex4ebook program.

My program versions are:

```

$ latex --version
pdfTeX 3.141592653-2.6-1.40.26 (TeX Live 2024/Parabola GNU/Linux-libre)
kpathsea version 6.4.0
Copyright 2024 Han The Thanh (pdfTeX) et al.
There is NO warranty.  Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.43; using libpng 1.6.43
Compiled with zlib 1.3.1; using zlib 1.3.1
Compiled with xpdf version 4.04

$ tex --version
TeX 3.141592653 (TeX Live 2024/Parabola GNU/Linux-libre)
kpathsea version 6.4.0
Copyright 2024 D.E. Knuth.
There is NO warranty.  Redistribution of this software is
covered by the terms of both the TeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the TeX source.
Primary author of TeX: D.E. Knuth.

$ tex4ebook --version
tex4ebook v0.3i

```

I am using this command to generate my EPUB 3 file:

```
tex4ebook -f epub3 main.tex
```

It successfully generates an `main.epub` file. When I try to validate
`main.epub` I use this command:

```
$ epubcheck main.epub
Validating using EPUB version 3.3 rules.
ERROR(RSC-005): main.epub/OEBPS/main.xhtml(3,14): Error while parsing file: Element "title" must not be empty.

Check finished with errors
Messages: 0 fatals / 1 error / 0 warnings / 0 infos

EPUBCheck completed
```

So, `tex4ebook` is creating an empty title tag. I have this code in my
`main.tex`:

```
(...)

\title{My awesome book}
\author{Daniel Cerqueira S.}
\date{August 2024}

(...)
```

Is this an `tex4ebook` bug?

How can I make sure that my EPUB file has a properly filled title tag,
using `tex4ebook`, so that my EPUB file is in compliance (using
`epubcheck`) ?