If you are using distribution packages or the copr repository, you don't need to deal with these files!
The unit file in this directory is to be put into /etc/systemd/system.
It needs a user named node_exporter, whose shell should be /sbin/nologin and should not have any special privileges.
It needs a sysconfig file in /etc/sysconfig/node_exporter.
A sample file can be found in sysconfig.node_exporter.