hugo/tpl/tplimpl/embedded/templates/schema.html

<meta itemprop="name" content="{{ .Title }}">
<meta itemprop="description" content="{{ with .Description }}{{ . }}{{ else }}{{if .IsPage}}{{ .Summary }}{{ else }}{{ with .Site.Params.description }}{{ . }}{{ end }}{{ end }}{{ end }}">

{{- if .IsPage -}}
{{- $iso8601 := "2006-01-02T15:04:05-07:00" -}}
{{ with .PublishDate }}<meta itemprop="datePublished" {{ .Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end}}
{{ with .Lastmod }}<meta itemprop="dateModified" {{ .Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end}}
<meta itemprop="wordCount" content="{{ .WordCount }}">

{{- with $.Params.images -}}
{{- range first 6 . -}}<meta itemprop="image" content="{{ . | absURL }}">{{ end -}}
{{- else -}}
{{- $images := $.Resources.ByType "image" -}}
{{- $featured := $images.GetMatch "*feature*" -}}
{{- if not $featured }}{{ $featured = $images.GetMatch "{*cover*,*thumbnail*}" }}{{ end -}}
{{- with $featured -}}
<meta itemprop="image" content="{{ $featured.Permalink }}">
{{- else -}}
{{- with $.Site.Params.images -}}<meta itemprop="image" content="{{ index . 0 | absURL }}"/>{{ end -}}
{{- end -}}
{{- end -}}

<!-- Output all taxonomies as schema.org keywords -->
<meta itemprop="keywords" content="{{ if .IsPage}}{{ range $index, $tag := .Params.tags }}{{ $tag }},{{ end }}{{ else }}{{ range $plural, $terms := .Site.Taxonomies }}{{ range $term, $val := $terms }}{{ printf "%s," $term }}{{ end }}{{ end }}{{ end }}" />
{{- end -}}