In Flow, links from one Wikimedia link to another show up with the link color and a small icon that is typically associated with an external link. This appears to be defined by class="external". If I'm reading the code correctly, there is not a problem with the way "nofollow" is set, but it would be good if somebody more familiar with HTML and CSS could take a look at that part to make sure; links from one Wikimedia wiki to another should be taken into account by search engine spiders. There are a few interwiki links in this comment, for example: https://www.mediawiki.org/wiki/Topic:Tit9gtsmop8qd2d8