\RequirePackage{latexml}

\tl_const:Nx \c_stex_html_emptyarg_tl {~}
\cs_new_protected:Nn \_stex_html_checkempty:n {
  \tl_set:Nn \l_stex_html_arg_tl { #1 }
  \tl_if_empty:NT \l_stex_html_arg_tl {
    \tl_set_eq:NN \l_stex_html_arg_tl \c_stex_html_emptyarg_tl
  }
}

\prg_new_conditional:Nnn \latexml_if: {p, T, F, TF} {
  \iflatexml
    \expandafter\prg_return_true:
  \else:
    \expandafter\prg_return_false:
  \fi:
}

\cs_new_protected:Nn \stex_annotate:nnn {#3}
\cs_new_protected:Nn \stex_mathml_intent:nn { #2 }
\cs_new_protected:Nn \stex_mathml_arg:nn { #2 }
\cs_new_protected:Nn \stex_annotate_invisible:n {}
\cs_new_protected:Nn \stex_annotate_invisible:nnn {}
\NewDocumentEnvironment{stex_annotate_env} { m m } {}{}

\prg_new_conditional:Nnn \stex_if_html_backend: {p, T, F, TF} {
  \prg_return_true:
}