/usr/lib/ruby/2.0.0/tk/after.rb is in ruby2.0-tcltk 2.0.0.484-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | #
# tk/after.rb : methods for Tcl/Tk after command
#
# $Id$
#
require 'tk/timer'
|