MediaWiki:Apihelp-query+wikisets-param-prop/en

What pieces of information to include.
 * type:Opt-in based (includes only specified wikis) or opt-out based (includes all wikis except specified).
 * wikisincluded:The wikis that are included in this wiki set.
 * wikisnotincluded:The wikis that are not included in this wiki set.