System extension

System extensions are Apple's supported method of adding low-level functionality to the of macOS.

History
Apple introduced system extensions in macOS Catalina (10.15) in 2019 as a more secure alternative to kernel extensions (kexts), which had been used in earlier versions of Mac OS X. Kexts, now referred to as "legacy system extensions, were deemed a security risk and deprecated by Apple. Starting in macOS 10.15.4, the continued use of kernel extensions would trigger a warning to the user. Support for kexts would start being phased out in macOS Big Sur except for Apple-approved enterprise developers. Any legacy kexts still installed would require user approval to be loaded upon every startup.

Both the modern system extensions as well as the legacy kexts can be managed through the Extensions pane of System Preferences.