hyperref - pdflang attributes

Question

I try the following MWE (with LuaLatex 1.12.0 and hyperref v7.00d) and have two problems/questions:

\documentclass[a4paper,11pt]{article}
\usepackage[ngerman]{babel}

\usepackage[unicode]{hyperref} 

\hypersetup{
    pdfauthor={ABC – https...},
    pdftitle={title with German öäüß},
    pdflang={de}
}

\usepackage{kantlipsum}
\begin{document}
    \kant[1]
\end{document}

1. In my PDF Viewers the language option is not displayed. I'm not sure if this is due to my PDFViewer or if this is not compiled into the PDF.
2. According to the documentation the pdflang should be RFC 3066. But looking for a list I didn't find one. When I follow the link from W3 I end up with ISO 639-2 codes. Are they now same or different?