Exporting html to PDF/UA

I am trying to export html to PDF/UA using command line tools. The export works but when I run the PAC tool against the resulting PDF I get 2 errors: “0000-00-00T00:00:00-04:00” is not a valid XMP date and “PDF/UA identifier is missing”. Does anyone know how I can set those values? Any help will be appreciated.

To fix the date I added a meta tag in the html documents head section:

<meta name="created" content="*well formatted date*>. Both errors are gone now. I understand why the date erro is gone but I'm suspicious of why the pdf/ua/identifier error is gone.

you may want to track it down the rabbit hole → https://opengrok.libreoffice.org/xref/core/vcl/source/pdf/XmpMetadata.cxx?r=d23c5560c13fc10ef367ae1d3bbf6c790dde2a61#232