if i created a permission with a kit, how do i delete that permission so it doesnt exist anymore? i mean deleting the permission itself, so it doesn't appear on my AdminMenu permission section.

remove the permission from the kit concerned using the kits gui menu or the config json

yeah i know that, i mean the permission from oxide, so that it does not exist anymore as a permission. for example, if i made the permission kits.starter, even if i remove the permission from the kit, the permission itself still exists and appears in permission manager.

I have never had a kit permission still appear in permissions manager after i have removed it , and once you have revoked the permission from players it cannot be used by them ,