/usr/share/xserver-xorg/xinputdep is in xserver-xorg-dev 2:1.19.6-1ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
xorg-input-abi-24, xserver-xorg-core (>= 2:1.18.99.901)