Only the current version so far — new entries appear as the app ships updates.
シンプルな勉強時間記録アプリ is a productivity app by T.O. with 500+ downloads (about 975 estimated). +41 installs in the last 7 days. Install growth, rank history, SDKs and ad networks.
From the store listing: “Record and manage your study time by task. Visualize your learning with a calendar view and statistics dashboard. A simple and easy-to-use free app.”