Project/source link-up field #55
Description
@kcrisman suggests (in PreTeXt drop-in development) that we could automate remixing PreTeXt books. (Cognizant of broken xref, mis-matched LaTeX macros, etc.)
So we know a book here in the project. And we could have @xml:id for various components. But we seem to want to have the connection between book and "master" PreTeXt/XML file. So a new entry in this catalog should provide this connection.