Much as I'd love to use this mod, I've been unable to find the information I need to do so. How do I open the quest editing GUI? What add-ons are available? Is there some stable API if I want to make an add-on myself?

Your forum thread and CurseForge page list all the features, but don't seem to say how to use them, and you don't have a Github wiki - have I missed the documentation, or is there not any?

The mod is less than a week old. I'm still writing all the documentation and guides

I'm glad to hear that you're working on it, and thank you for making this mod.

Although the mod now has an in game starter guide I'm going to keep this issue thread as a reminder to continue making the more detailed wiki pages.

Is there any documentation on the json format for those of us who like to use an external editor?
Edit: Maybe add a json-schema?