/usr/src/linux-source-4.4.0/debian.master/control.d/vars.powerpc64-smp is in linux-source-4.4.0 4.4.0-22.40.
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 | supported="64-bit PowerPC SMP"
target="Geared toward desktop or server systems."
desc="64-bit PowerPC SMP"
bootloader="yaboot"
provides="redhat-cluster-modules, ivtv-modules"
arch="powerpc"
|