There was a typo, seemingly, because in linux/fuse.h these constants are
defined as

	#define FUSE_HANDLE_KILLPRIV	(1 << 19)
	#define FUSE_POSIX_ACL		(1 << 20)

(https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fuse.h?id=v5.0-rc6-46-gcb5b020a8d38#n282)