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I thought that was a peculiar choice of words as well. I would understand these things under the banner of "Build Engineering", or even just "Tooling". I couldn't figure out the distinction they wanted to make by calling it "Metaprogramming".

That was raised as an issue a while ago: https://github.com/missing-semester/missing-semester/issues/...

The answer is basically "sure, but we explain what we mean in the lecture."

You don't have the wrong definition, I had the same thought as you. They are definitely using a non-standard definition of that term, although I suppose it makes some sense if you look at it the right way (sort of like "metadata" in a way).