kext_logging(8) on macOS
The text 54b8c94809f8, as macOS 11.0.1, macOS 10.15.6, macOS 10.15.5, macOS 10.15.4, macOS 10.15.3, macOS 10.15.2, macOS 10.15.1, macOS 10.15 shipped it.
verbose/logging flags for kernel extensions (kexts) in the kernel and command-line utilities