This file is indexed.

/usr/share/gromacs/top/tip4p.itp is in gromacs-data 2018.1-1.

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

The actual contents of the file can be viewed below.

1
#error   This top-level .itp file has been removed. Edit your topology to include it from your force field directory instead, e.g. "oplsaa.ff/tip4p.itp"