/etc/modprobe.d/amd64-microcode-blacklist.conf is in amd64-microcode 3.20171205.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | # The microcode module attempts to apply a microcode update when
# it autoloads. This is not always safe, so we block it by default.
blacklist microcode
|