For schemas in multiple documents referencing each other with include, redefine, or import, does the check cover the entire set of documents?
Yes. If the schemaLocation attributes on these elements can be de-referenced, XML Schema Quality Checker will load all documents and include them in the quality check. Depending upon whether you accept the default of -entireSchemaValid or use -requireEachDocumentValid, the tool may issue additional messages (with the second option) if the documents are not valid schemas by themselves, even if they are valid when viewed as a whole.