The Grim extension

The Grim extension lets you import game data from the official BOTC app. During a game, or during the grim reveal (for best results), you can click the extension icon to make a QR code appear. You can then scan that QR code via The Grim app by clicking the "Import from official app" button under Menu -> Stats -> Import from official app. The Grim app will then load the game data, so you can save it and add it to your stats.