I was recently looking into how I could cut down on some of my BSP stairs until i get some actual models done, and wasn’t sure how to properly use the Geometry Editing Mode and using its Brush Clipping mode - so I went on a documentation hunt.
What turned up was Geometry Brush Actors - Geometry Editing Mode which sends me elsewhere for details:
Following the link, I end up in Level Editor Modes which only has this brief info in the table:
Those two are sending users in a loop and never actually tell anything about the details of Geometry Editing mode.
Either the Link for details on the Geometry Editing Mode is wrong, or the Editor Modes page lost some of its content somewhere along the way.