Schema extension

I freely acknowledge the goal of an XML schema that can be modified and extended for local conditions is of vital importance and is often overlooked in XML efforts.

However, once semantics are defined for the 115 instances of attributes in the Akoma Ntoso schema, the ability to modify and/or extend the schema will be severely impaired, without the dangerous proposition of editing the original schema. (I assume some attribute names appear more than once since 4.1.1 says there are 61 attributes. Yes?)

It is a big ask at this point in the process but patterns, RELAX-NG and no attributes (elements only) would greatly enhance the ability of this schema to be extended and adapted by others. You don't need to take my word for it, see RELAX NG by Eric van der Vlist, Chapter 12, Writing Extensible Schemas.

For existing applications, you could export XSD versions of their existing schemas and take advantage of the extension (such as interleave) capabilities of RELAX-NG, resulting in modular schemas that can be invoked and extended as needed.