By tapping this icon you can swap between the current bubble and the next bubble. The text in the middle lets you know how many bubbles you have left to beat the level with.

Tapping the Pause button in the top left will allow you to Replay, Return to the Saga map with the Home button, and change the audio options.

In the top right corner you’ll see a counter showing the number of bubbles left to be popped on the board.