Changing map properties

[testerpester2]

Is there a way to change the map properties, like which skybox the map is meant to use? I can't seem to find anything, and the VMF files don't seem to have anything in them that would hint at a way to change the skybox manually

[erysdren]

select any brush that isnt func_detail or whatever and go to the "Entity" tab in the editor, the map properties will be there (they are the properties of worldspawn, the root entity of the map)