org: Quoting HTML tags
12.6.4 Quoting HTML tags
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Plain ‘<’ and ‘>’ are always transformed to ‘<’ and ‘>’ in HTML
export. If you want to include raw HTML code, which should only appear
in HTML export, mark it with ‘@@html:’ as in ‘@@html:<b>@@bold
text@@html:</b>@@’. For more extensive HTML that should be copied
verbatim to the exported file use either
#+HTML: Literal HTML code for export
or
#+BEGIN_HTML
All lines between these markers are exported literally
#+END_HTML