hugo-theme-termlite/layouts/_default/_markup/render-heading.html

{{- $pageWantsAnchors := .Page.Params.renderHeadingAnchors | default true -}}
{{- $anchorEnabledForThisHeading := .Attributes.anchor | default true -}}
{{- $hasAnchor := and $pageWantsAnchors $anchorEnabledForThisHeading -}}
<h{{ .Level }} id="{{ .Anchor }}" class="heading{{ if $hasAnchor }}  with-anchor{{ end }}">
  {{- if $hasAnchor -}}
    <span class="heading__anchor">
      <a href="#{{ .Anchor }}">{{ range seq .Level }}#{{ end }}</a>
    </span>
  {{- end -}}
  {{ .Text | safeHTML }}
</h{{ .Level }}>