Creating custom metadata for Quarto project book

[eeholmes]

Background: This is for a Quarto extension. This stopped working with Quarto v1.2 https://github.com/nmfs-opensci/quarto-thesis

With the Quart 1.2 release, on-the-fly creation of metadata stopped working. So a project with this _quarto.yml will now throw an error saying that custom-metadata is not an allowed metadata variable.

_quarto.yml

project:
  type: book
  output-dir: .

book:
  title: A title
  custom-metadata: "test"

Can I define new metadata somewhere?

The documentation page doesn't discuss defining new metadata just customizing the pre-defined metadata for a project type.
https://quarto.org/docs/extensions/project-types.html
It doesn't say if one can create a new project type either like you can create a new format type.

I am using Quarto 1.2.246 .

[eeholmes]

Nevermind. I got it working. I just changed to

book:
  title: A title

thesis:
  custom-metadata: "test"

And refer to $thesis.custom-metadata$ in my LaTeX partials.