What types of kexts will not load in macOS 11?

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?


From the release notes for macOS Big Sur beta:

Kernel extensions using certain deprecated KPIs no longer load. Refer to the support page. While macOS Big Sur remains in development, you can temporarily disable System Integrity Protection to allow these deprecated extensions to load. (55068348)