Last modified: 2014-10-29 07:31:12 UTC
There should be a prop=relatedsites module which provides a list of all the related sites. This will be extremely useful during the Wikidata migration when trying to connect a Wikivoyage page with the Wikidata one. For some reason the original version of the mw documentation page claims it uses the API, but I can't find anything in the code to indicate that. (https://www.mediawiki.org/w/index.php?title=Extension:RelatedSites&oldid=595097).
Unfortunately I have no experience with the API and how to work with the Git repository so I will give at least two ideas: (1) The API function should be similar to prop=langlinks (ll) (2) From the public function onSkinTemplateToolboxEnd( &$skinTpl ) (at the end of RelatedSites.class.php) you can learn how to access to the stored values: $relatedSites = $this->getCustomData()->getSkinData( $skinTpl, 'RelatedSites' ); if ( count( $relatedSites ) == 0 ) { return true; } $relatedSitesUrls = $this->getRelatedSitesUrls( $relatedSites ); foreach ( (array) $relatedSitesUrls as $url ) { $href = htmlspecialchars( $url['href'] ); $text = $url['text']; ... } Now you can check for Wikipedia and Commons. $url['text'] should contain "Wikipedia", "Wikimedia Commons" and others.