Thanks. I still don't know what the activities are but nice to know I can get rid of them
Update - it sounded like a good idea. After installing and logging out/in I now have no desktop icons. There is a cashew with the caption "desktop icons" on a blank screen. Clicking the cashew just gives me a menu.
Got the icons back by changing to folder view. Am left with an ugly "desktop icons" cashew. This sucker is ugly and in the way of my weather. Suppose I can make my weather widget opaque.
Not sure if the nac script or kde updates did this, probably the KDE updates.