Is there a schema (preferably commented) for concrete5-cif anywhere? That would be good documentation.
A proper schema would also provide a way to verify that whatever you end up putting together if you do it from scratch is syntactically and semantically correct, using common xml tools.
I’ve been thinking about an XML Schema (XSD for short) for years.
Now I finally found the time to start working on it: see GitHub - concrete5-community/concrete-cif: Validation of Concrete CIF files
Just a couple of notes though.
First of all, it’s still a work in progress, I think I’ll reach an usable version in a week or two.
Second, given the complexity of Concrete CIF files, XSD 1.0 is not enough: we need 1.1.
The problem is that 1.1 is not supported by PHP and many IDEs (VSCode Eclipse, … not sure about others).
And the only open source library that supports 1.1 seems to be Xerces (and for this reason the project above also comes with a Java program you can use to check CIF files).