[DNSB]

This is what I see when embedding a subtitle in an ePub using calibre (the subtitle is "Daring Adventures on Elephant Island":

<meta name="calibre:user_metadata:#subtitle" content="{&quot;table&quot;: &quot;custom_column_9&quot;, &quot;column&quot;: &quot;value&quot;, &quot;datatype&quot;: &quot;text&quot;, &quot;is_multiple&quot;: null, &quot;kind&quot;: &quot;field&quot;, &quot;name&quot;: &quot;Subtitle&quot;, &quot;search_terms&quot;: [&quot;#subtitle&quot;], &quot;label&quot;: &quot;subtitle&quot;, &quot;colnum&quot;: 9, &quot;display&quot;: {&quot;description&quot;: &quot;&quot;, &quot;use_decorations&quot;: 0}, &quot;is_custom&quot;: true, &quot;is_category&quot;: true, &quot;link_column&quot;: &quot;value&quot;, &quot;category_sort&quot;: &quot;value&quot;, &quot;is_csp&quot;: false, &quot;is_editable&quot;: true, &quot;rec_index&quot;: 31, &quot;#value#&quot;: &quot;Daring Adventures on Elephant Island&quot;, &quot;#extra#&quot;: null, &quot;is_multiple2&quot;: {}}" />