On mobile style sheets, ##<blockquote>## is decorated by
content: open-quote; }
content: close-quote; }
That should be completed by language dependant definition of quotation marks. Project language (fallback to English) might be starting point, but could be based on page content or even section language.
See http://www.w3.org/TR/CSS2/generate.html#quotes-specify for required code.
Please find some major language customs [[https://de.wikipedia.org/wiki/Wikipedia:Lua/Modul/Text/Test#quotMarks | here]] or [[https://de.wikipedia.org/wiki/Modul:Text | as code]].