This is 'plymouth-disabler'.

plymouth-disabler is a package you can install to disable plymouth.

You may wish to do this if plymouth is problematic for you, but you cannot
remove it due to dependencies.   One such reason for such a scenario is
described in bug 1235231 (http://pad.lv/1235231).

This package works by using postinst and postrm maintainer scripts to manage a
line in a .override file in /etc/init for each known plymouth upstart job.

For example, after installation, you will have a file
'/etc/init/plymouth.conf.override' which contains the line
  manual #MANAGED_BY_PLYMOUTH_DISABLER

On removal of the package the line will be removed.
After removing that line, if the file is empty (zero length) then the file will
also be removed.
