Hey ,
I think most of the confusion is coming from the change of BSP to Geometry mode. There was originally BSP documentation that was left over from udk/ue3 docs but once Geometry became the new way of doing things a lot of the older docs were redone. Now as for those tools/options (Edit, Brush Clip, Lathe, Extrude, Pen) under Geometry editing mode I can put in a request for better clarification on those features.