At 4:15 in https://developer.apple.com/videos/play/wwdc2020/10210/, the on-screen text says "In macOS Big Sur, kexts that were deprecated in macOS Catalina will not load." The speaker, however says that they will not load "by default." What classes of kexts will be deprecated? What will the user experience look like when a kext is blocked? Will the user be given a chance to authorize it anyway?