Been using the new features in my mods and there's an unexpected result from the changes.
Previously, any terrain assigned to a texture would be overridden by terrains listed on alienDeployments or ufo entries. Or at least I was under the wrong assumption. But with the latest changes this has been reversed: terrains assigned to textures override any terrains listed on those sections.
This happened because Supsuper's rationale was that this change would allow to specify terror site terrains for specific locations such as cities. However, this applies to Geoscape textures as well, which are causing issues with some existing mods. While before I could determine a specific terrain for a UFO mission, regardless of its Geoscape texture, now that isn't possible anymore.
So I'd propose to go back and have terrains listed on alienDeployments or ufos override the ones listed under textures, unlike the present solution. It will still be possible to define specific terrains for terror sites on cities by creating an unique texture, which was the original intention behind the change, and it will allow to customize the terrain for UFOs/Terror Sites through alienDeployment or ufo entries, which was the previous system and allows for more customization.