Edits project.ypf, opened from the Project Editor. Full schema: project.ypf.

• Name - the project's display name.
• Description - a short plain-text summary.
• Notes - Markdown, shown on the project's page in the online library.
• Categories - labels for the library.
• Default canvas size - width, height and background color used by addPage() calls that don't set their own, and by the Overlay Editor's blank canvas. A page's real size comes from process.js.