Only the current version so far — new entries appear as the app ships updates.
危険物取扱者試験 乙種第4類 「30日合格プログラム」 is an education app by ReCorrect Inc. with 100+ downloads (about 390 estimated). +1 installs in the last 7 days. Released Oct 18, 2018. Install growth, rank history, SDKs and ad networks.
From the store listing: “[Android's first] Hazardous materials handler test Class B 4th class full-scale learning app!
Equipped with an efficient learning schedule and a mock exam that changes questions every time!
If you only have this, you don't need a reference book!”