What are these KM folders in "/private/var/folders/vl/x6z6g6y54gvg60cxn85jgnj80000gn/T/"?

I have a lot of folder under the directory:
(I discovered this when I click to open a downloaded zip file from the MS Edge browser, which itself is odd, since in my setting, the default folder for downloaded items is set to the "~/Downloads" folder. But the download file is saved to this place.)
There are many others, but a lot of them belong to KM. The KM folders are all blank. Some others are not blank. They all have "Export" as part of the folder name. A folder is generated every time I export a KM macro? Will they be deleted automatically at some point? Is it safe to delete all the items here?

@peternlewis, calling for your attention.

The /private/var/folders directory is the system location for temporary or cache files.

The system deletes them whenever you restart.

The Keyboard Maestro Export files are creates when your use the Share facility to export files. Keyboard Maestro can't delete them because it isn't told when the sharing service is done with the files (perhaps it could in the specific case of sharing to the forum, since that comes back to Keyboard Maestro, but not in the general case).