The script, and the code the script downloads, both come from the same repo and were written by the same developer.

If you've already decided you trust the author, what's the actual threat here?

I would not trust the author just like that.

But then again, I'm a bit paranoid. At a minimum I would download the script and read it, and if it was too long or not written clearly enough then I would just drop it and find something better.