Manual:$wgStyleVersion/ja

詳細
グローバルのスタイルシートや JavaScript を変更した際に、この番号も増やします.

It should be appended in the query string of static CSS and JS includes, to ensure that client-side caches don't keep obsolete copies of global styles.

'''この値を変更する必要はあありません. ''' In addition the default values are not documented, as the actual value of this setting has no significance (except to note that it will be different, and higher, in each version of MediaWiki).