Blue thing on my Twitter tab.
It appeared after I updated today. If the number is small enough, it is the same number Twitter puts up for unread tweets. What is the purpose of this? Pages with unread messages already get unread notifications in the tab title. This blue thing is just ugly, and repeats information already available (except when it doesn't, and is just blue and ugly). Turning off "Detect Page Title Notifications" to make it go away. Turning off the very similarly named option "Use Unread Indicators" did not affect it. What is the purpose of these options?
@mikecrews - It's a notification label. The number will only show from 1-9. Above that, it shows "+".
That's just to save space. It's assumed that a lot of people who hope to use this number, will be seeing on pinned tabs. Therefore, there's no room for two or more digits.