/usr/share/doc/apt/examples/preferences is in apt 1.6.1.
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 9 10 11 | Package: *
Pin: release a=stable
Pin-Priority: 500
Package: *
Pin: release a=testing
Pin-Priority: 101
Package: *
Pin: release a=unstable
Pin-Priority: 99
|