matrix-spec-proposals/layouts/partials/hooks/body-end.html

{{/*

  This template is included at the end of each page's `<body>`.

  We're using it here to:

  1) include the JS that generates the table of contents. It would be better
  to generate the table of contents as part of the Hugo build process, but
  that doesn't work nicely with the way we want to author client-server modules
  as separate files.

  2) highlight and scroll the ToC in the sidebar to match the place we are at
  in the document.

*/}}

<script defer language="javascript" type="text/javascript"  src="{{ "js/toc.js" | urlize | relURL }}"></script>