/etc/maas/templates/pxe/config.install.arm64.template is in maas-cluster-controller 1.5.4+bzr2294-0ubuntu1.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | DEFAULT execute
LABEL execute
{{# SAY is not implemented in U-Boot }}
KERNEL {{kernel_params | kernel_path }}
INITRD {{kernel_params | initrd_path }}
APPEND {{kernel_params | kernel_command}}
IPAPPEND 2
|