The rewritten Style Guide has an open discussion of the spoiler policy. The current policy will be used if no new consensus is reached. Discuss it here.
Has subobject"Has subobject" is a predefined property representing a <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Container">container</a> construct and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.