aboutPage.jsx

...

const AboutPage = ({ data }) => {
  const { markdownRemark: page, footerData, navbarData } = data;
  const {
    frontmatter: {
      seo: { title: seoTitle, description: seoDescription, browserTitle },
    },
  } = page;

  return (
    <Layout footerData={footerData} navbarData={navbarData}>
      <Helmet>
        <meta name="title" content={seoTitle} />
        <meta name="description" content={seoDescription} />
        <title>{browserTitle}</title>
      </Helmet>
      <AboutPageTemplate page={{ ...page, bodyIsMarkdown: false }} />
    </Layout>
  );
};

AboutPage.propTypes = {
  data: PropTypes.object.isRequired,
};

export default AboutPage;

...