+ * @param WANObjectCache $cache A cache manager for caching blobs. This can be the local
+ * wiki's default instance even if $wikiId refers to a different wiki, since
+ * makeGlobalKey() is used to constructed a key that allows cached blobs from the
+ * same database to be re-used between wikis. For example, enwiki and frwiki will
+ * use the same cache keys for blobs from the wikidatawiki database, regardless of
+ * the cache's default key space.