react-bootstrap/react-bootstrap — pull request #125 by mathieumg (2014-06-20 01:09:50+00:00)
Title: Make it possible to provide a renderable as a label to a progress bar

Other components do it (`` for the tab label comes to mind), I don't see why we wouldn't want to generalize a bit here, if anyone wants to add a child to an already nested progress bar or if someone wants better control over how the percentage is displayed (currently the value is ceiled).