libxxf86vm1-dbg software package provides X11 XFree86 video mode extension library (debug package), you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libxxf86vm1-dbg
libxxf86vm1-dbg is installed in your system.
Make ensure the libxxf86vm1-dbg package were installed using the commands given below,
$ sudo dpkg-query -l | grep libxxf86vm1-dbg *
You will get with libxxf86vm1-dbg package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Library development |
| Package | libxxf86vm1-dbg |
| Version | 1:1.1.3-1 |
| Description | X11 XFree86 video mode extension library (debug package) |
| Sub Section | libdevel |