David -
Are you making GDScript a language for ActiveCode programs? Or just static listings? If the former, you will need a seperate PRs on both PreTeXt and Runetone.
All of the PR's for PreTeXt go through Rob. But, if you have done the work to find and follow Dave's changes, your PR is likely in good shape. And adding a new language is not going to inspire a deep debate. It should be fine to just open the PR.
I'm personally interested in your project for some high school teachers I work with, but I'll follow up off the list about that.
Andrew Scholer