What script is included with the kernel source to patch a kernel?

`update-kernel` is not a standard script included with the kernel source for patching, though similar names exist for other kernel-related tasks like updating initramfs.

The `patch-kernel` script is a utility, often included within Linux kernel source distributions or development toolsets, that is specifically used to apply patches, especially incremental ones, to the kernel source tree. It simplifies the patching process by managing patch levels and ensuring correct application.

`apply-patch` is a generic term, but not the specific name of the script included with the kernel source for this purpose.

`patch` is the general-purpose utility used to apply diff files, but `patch-kernel` is the specific *script* that orchestrates kernel patching, often utilizing the `patch` utility internally.