I think it's a TWC cliff face texture.
TAD terrains and props overall did seem somewhat less rich in texture and flavour than the original. I don't really have a problem with weapons caches being monomorphic because there are only so many ways to package and store explosives, and the scenario you're referring to takes place in a British-controlled enclave.
One of the things I've seen sziggi do that I'd like to make part of a switchable mod, is use cliff face terrains and textures, building textures, and land terrain textures interchangeably.
For instance, use the brickwork texture on the outside of the European fort for a thick wall you make out of raised terrain, so you can shoot down on people from it.
Or using the blue and white tiled patterns from the Sufi native buildings to re-skin some Ottoman buildings.
I don't think such a mod would even require uninstalling to go online and share scenarios. Technically there's no strategic advantage to enabling these textures in custom maps. (Of course, if you enable it for any map whatsoever, a guy could disguise which civ he's playing entirely by re-texturing all his buildings. That would be a hilarious hack...build a barracks and it looks like a farm. Then some jans come out...)
Crunkatog on ESO
Bart331 balance suggestion: aztec: remove civ
Voltiguer: Ender, Sioux in 1.04 will be a top civ, no matter how many layers of Sioux goggles you put on
schildpad on Elephants: ...their mansabdar unit sucks so hard it looks like a black hole
Crunkatog on Steam.