It is evident that the pyroland textures are separate, or embedded into the maps in some form. Some official maps have it, some do not. Has there been any announcement or info as to how we can put pyroland textures onto maps?
In theory, not only could you give the map alternative textures, you could have a different aesthetic choice entirely.
Pyroland is accomplished via shader, in some materials folders there is a "replacements.vmt" that specifies keyvalues to insert into materials. These keyvalues come in sets, for example, there can be a "brick" set that affects all the materials in that folder with "brick" in the name. These keyvalues tint, add the stripe, and adjust the lightmaps. They also add a "grey step" which I think is palletted color or lighting values. I think there's a bit more to the parameters but I didn't dig very deep.
Don't know how it determines which maps have pyroland.