Link: ★★ゲーム本体 抽出方法 | 幻想娘Games
parts 1 and 2 of the zipped file are free, but part 3 is behind a monthly subscription paywall on Pixiv or Fantia
Pixiv Link: https://eluku99.fanbox.cc/
Fantia Link (post limit is 2 links or I’d put it here too, but it can be found on the eluku page linked above)