A user has an annotation system goes by name "STF".
These annotations need to live in the same DFDL schema as DFDL annotations. .
They are isolated in their own xs:appinfo blocks with different source URI.
The problem is that this annotation language uses XML attributes on some of its annotation elements (just as DFDL does).
And there's the problem.... this annotation language has xs:attribute declarations, and Daffodil issues an SDE because of them, because we don't know that they aren't intended to be (mistakenly) used for data. We don't have a way of knowing they're only for an annotation language that we'll be ignoring.
We need a mechanism to tolerate these without turning off checking for misuse of DFDL-disallowed XML constructs entirely.
Possibilities might be to issue an SDW, but have a means for suppressing this SDW so that users with this situation don't have to put up with lots of SDW messages. Another idea is to have a dfdl:ignore annotation that can be placed on an xs:include/xs:import telling Daffodil to not carry out that import. Another possibility is to add XSD1.1 features for conditional preprocessing of schemas.