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.
"Schema tag" is a predefined property provided by Semantic MediaWiki to identify a collection of schemata. A label that identifies schemata of similar content or characteristics. This property is pre-deployed (also known as special property) and comes with additional administrative privileges but can be used just like any other user-defined property.