Ubuntu – How to know the source ppa of an installed package

The version 2.20.0 is a local package on your system, because it has no source repository currently associated with it. That means, either you have installed it as a .deb file manually, or you had an other source temporarily added in the past. My guess is, that you had the ppa:ubuntu-x-swat/intel-graphics-updates added to the software sources sometime earlier, did an upgrade, and later you have removed it or changed it to ubuntu-x-swat/x-updates. Based on the exact version string of the xserver-xorg-video-intel package, this seems obvious:

PPA name:       ubuntu-x-swat/x-updates
Latest version: 2:2.19.0-0ubuntu1~xup1

PPA name:       ubuntu-x-swat/intel-graphics-updates
Latest version: 2:2.20.0-0ubuntu0~precise1

Here you can find a more recent version of this driver (2.21.6):

ppa:glasen/intel-driver

If you want to downgrade a package, you have to specify the exact version number to install:

sudo apt-get install xserver-xorg-video-intel=2:2.19.0-0ubuntu1~xup1

You need the ppa-purge utility to downgrade all the packages installed by the PPA and disable the PPA.

Since you have removed the PPA from your sources list, you have to add it back.

Then, run:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:<your_ppa_name_here>

Then you can install LibreOffice 3 from the official repositories.

Regards.