SOUNDS CAN BE DISABLED!
Changes in 1.3: Options page fix-up.
Changes in 1.2: Fixed sound for content that arrives later. Icons were cleaned up.
Changes in 1.1: Improved icons by James Woodward.
+ "Your browsing history" : used to enable 1-up icon only on plus.google.com (extension permission "tabs").
+ "Your data on plus.google.com" : used to insert images, css and sounds.