Sorry to be confusing. I'm trying to convert a text file to pure HTML, and then use Calibre to read that file and eventually convert to ePub.
When I use the "meta" element inside that simple HTML file, Calibre does read and use "author" meta elements, but does not use Subject, Tag, Keyword, etc. meta elements to create Calibre tags.
I'd like to know if any specific meta element is supposed to work inside HTML to create Calibre tags.
The alternative will be to create ZIP files of my own with Manifests, etc.