This file is indexed.

/usr/share/xserver-xorg/xinputdep is in xserver-xorg-dev-lts-xenial 2:1.18.3-1ubuntu2.3~trusty4.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

1
xorg-input-abi-22, xserver-xorg-core-lts-xenial (>= 2:1.17.99.902)