What does "(2)" before a site name on a tab mean?

[rseilersj]

After a certain number of tabs on the same site are opened (I often see this on Youtube), subsequent tabs have "(2)" before the name. You can see it on the tab itself (including hover)and when you click the button to the right of tabs to display all tabs.

So, for example, the title should read:

"The Fountain of Youth"

But instead reads:

"(2) The Fountain of Youth"

[Passenger]

The tab title comes from the site itself.
It might mean something like 2 messages waiting for you.

For more precise answer ask the site.

[rseilersj]

Huh, thanks, that never occurred to me. I'll watch for that next time.