Does this add a new item?

No. It changes vanilla landfill's allowed placement tiles.

Does this replace foundation?

No. Foundation remains unchanged. This only lets landfill cover lava and oil ocean tiles.

Does this affect Aquilo oceans?

No. It does not touch Aquilo's ammoniacal ocean, brash ice, or ice platform behavior.

Is this safe for UPS?

Yes. The mod has no runtime script. It changes prototype data while the game loads.

Is this safe for existing saves?

Yes. You can add it to an existing save. Removing it only removes the expanded placement rule; already placed landfill remains vanilla landfill.

Does this affect achievements?

Like other mods, enabling it marks the save as modded for achievement purposes.

Does it work with other mods?

It should work with most data-stage mods that edit landfill. Mods that script their own landfill replacement behavior may conflict.