Comment 4 for bug 538474

$ apt-cache show xmodmap
N: Can't select versions from package 'xmodmap' as it purely virtual
N: No packages found

$ apt-cache search xmodmap
x11-xserver-utils - X server utilities
python-mmkeys - Multimedia key support as a PyGTK object
xkeycaps - manipulate X11 keymaps (for xmodmap) graphically

$ apt-cache show x11-xserver-utils | grep xmodmap
Replaces: iceauth, sessreg, xbase-clients (<< 1:7.3), xgamma, xhost, xmodmap, xrandr, xrdb, xrefresh, xrgb, xset, xsetmode, xsetpointer, xsetroot, xstdcmap, xutils (<< 1:7.2), xvidtune
Conflicts: iceauth, sessreg, xgamma, xhost, xmodmap, xrandr, xrdb, xrefresh, xrgb, xset, xsetmode, xsetpointer, xsetroot, xstdcmap, xvidtune
  - xmodmap, a utility for modifying keymaps and pointer button mappings in X;

$ apt-cache show x11-xserver-utils | tail -n 28
Description: X server utilities
 An X client is a program that interfaces with an X server (almost always via
 the X libraries), and thus with some input and output hardware like a
 graphics card, monitor, keyboard, and pointing device (such as a mouse).
 .
 This package provides a miscellaneous assortment of X Server utilities
 that ship with the X Window System, including:
  - iceauth, a tool for manipulating ICE protocol authorization records;
  - rgb;
  - sessreg, a simple program for managing utmp/wtmp entries;
  - xcmsdb, a device color characteristic utility for the X Color Management
    System;
  - xgamma, a tool for querying and setting a monitor's gamma correction;
  - xhost, a very dangerous program that you should never use;
  - xmodmap, a utility for modifying keymaps and pointer button mappings in X;
  - xrandr, a command-line interface to the RandR extension;
  - xrdb, a tool to manage the X server resource database;
  - xrefresh, a tool that forces a redraw of the X screen;
  - xset, a tool for setting miscellaneous X server parameters;
  - xsetmode and xsetpointer, tools for handling X Input devices;
  - xsetroot, a tool for tailoring the appearance of the root window;
  - xstdcmap, a utility to selectively define standard colormap properties;
  - xvidtune, a tool for customizing X server modelines for your monitor.
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu
Supported: 18m
Task: ubuntu-desktop, ubuntu-uec-live, kubuntu-desktop, kubuntu-mobile, kubuntu-netbook, edubuntu-desktop, edubuntu-uec-live, xubuntu-desktop, mythbuntu-backend-master, mythbuntu-backend-slave, mythbuntu-desktop, mythbuntu-frontend, ubuntu-netbook

$ apt-cache policy x11-xserver-utils
x11-xserver-utils:
  Installed: 7.5+2ubuntu1
  Candidate: 7.5+2ubuntu1
  Version table:
 *** 7.5+2ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ natty/main amd64 Packages
        400 http://us.archive.ubuntu.com/ubuntu/ maverick/main amd64 Packages
        100 /var/lib/dpkg/status

$ lsb_release -dr
Description: Ubuntu natty (development branch)
Release: 11.04