Conform Normals (Faces)

The Conform Normals tool sets all normals on the selected face(s) to the same relative direction.

ProBuilder uses the direction that most of the selected faces on the object are already facing.

In this example, all three selected faces on this cube end up pointing away from the Camera, as the Transform gizmo shows. This is because two out of three of the selected faces are pointing in the opposite direction, even though the majority of the normals are pointing towards the camera.