https://github.com/twitter/bootstrap/blob/3.0.0-wip/less/grid.less#L22-L24 https://github.com/twitter/bootstrap/blob/3.0.0-wip/less/gri... You might be looking

https://github.com/twitter/bootstrap/blob/3.0.0-wip/less/grid.less#L22-L24 https://github.com/twitter/bootstrap/blob/3.0.0-wip/less/gri... You might be looking at the 2.3.1 (master) branch, which didn't use border-box :).