For some reason I see both the Ubuntu 185 and 195 drivers in the Ubuntu Update Manager. In the NVidia X server settings I see the driver as version 185.18.36. I think I managed to install two versions of the NVidia drivers at the same time.
migrated from serverfault.com Feb 16 '10 at 20:05
The mod aliases are just PCI IDs used to tell xorg to load the prorprietary nVidia drivers for video cards with those IDs. There is now no Xorg.conf file by default anymore, so apparently this is a helper as part of the autoconfig system.
The different binary driver revisions support different hardware (nVidia doesn't keep support of older cards in newer drivers) and the different packages reflect that.
If you don't have the nVidia proprietary drivers installed these packages don't have meaning and can be removed.