Manual:$wgCookieSetOnAutoblock/ja

詳細
The cookie that is set will expire when the block expires or after 24 hours, whichever is shorter. つまり、無期限ブロックの Cookie は24時間後に期限切れになります.

The cookie is named 'BlockID', prefixed with. その値は、ハッシュされたブロック ID だけで、他のデータはありません.

If  is set to false, no cookie will be set during the creation of an autoblock.

See Autoblock#Tracking for more information.