Exactly as I thought.
It is a radio update, not sure if it matches the Optimus S or not though.
I can pull the radio img and make a flasher if anyone wants that, but it may need a different radio driver. Which could break compatibility with all current roms.
It is a full rom, 2.2.2, while not GB, it shows VM may intend to keep this phone around a bit longer. So we may see GB yet. The radio may contain a PRL update but I have no way to check without flashing it.
This WILL remove root.
It may not destroy your phone, and it won't destroy your data, it WILL remove Superuser and the ability to tether. Superuser is easy to replace with a flash, if it doesn't remove the custom recovery, but I can't be certain that it won't destroy that.
Edit:
Yes this destroys recovery as well.
So all root will be lost.
It can simply be repackaged to not lose root, but other than the radio, there is really nothing here for rooted users.