Where it comes from
The line in the source
pg=730 | hitCnt 84 | 強化拡張パック「双璧のファイター」 | 2021年 3月19日（金） Explore / Figure
Record
Cards in set (card-search hitCnt), released 19 March 2021
84 cards Released 19 March 2021
ReportedReported by a reliable secondary source, or read carefully from filed documents.