center

<..ooffice begin-end env ..>+

\ConfigureEnv{center}
   {<.begin env section .>\HCode{}}
   {<.end env section .>%
    \HCode{}\par<.try env inline par .>}
   {} {}
\ConfigureList{center}
  {}{}{<.HtmlPar at center .>\par}{}

-_-_-

The \par at the end of \ConfigureEnv{center} is required for cases like the following one.

\documentclass[titlepage]{article}
\begin{document}
    \begin{abstract}
    file. (see below)

    file. (see below)

    file. (see below)
    \end{abstract}
\end{document}

<..HtmlPar at center ..>

\Configure{HtmlPar}
    {\EndP \HCode{<text:p text:style-name="center"  >}}
    {\EndP \HCode{<text:p text:style-name="center"  >}}
    {\HCode{</text:p>}}
    {\HCode{</text:p>}}%

-_-_-

<..ooffice begin-end env ..>+

\NewConfigureOO{center}
\ConfigureOO{center}
   {\Hnewline
    <style:style style:name="center"
              style:family="paragraph"
              style:parent-style-name="Text-body"
              style:next-style-name="Text-body">
<style:paragraph-properties  fo:margin-top="0.199cm"
              fo:margin-bottom="0.199cm"
              fo:text-align="center"
              style:justify-single-word="false">
    <style:tab-stops/>
</style:paragraph-properties >
</style:style>\Hnewline
    }

-_-_-

1.7.5 center