As for the resource itself, you could likely find it in the editor and use the migrate function to export it to a different project or folder structure. This is likely the best idea as that material instance references an actual material, which references a one or more textures, all of which you’ll need for the appearance of a skysphere if you’re building it the same way as in the example map.
Before going further, can you be more clear on
1: What you’re actually wanting to accomplish and
2: Why you’re wanting to create a C++ class for what amounts to a specific prop that doesn’t have high computational intensity.