The two tragged values "extensionName" and "extensionVersion" are mapped to XML attributes for instances that are created from an extended schema. They are defined in that schema as XML attributes of the D2LogicalModel class.
The claim for level B extensions is that all valid instances are also valid against the "big" schema (i.e. as a reference).
The full schema does NOT contain the definition of the "extensionName" and "extensionVersion" XML attributes.
Hence, a valid of an extended schema that does have occurences of the "extensionName" or the "extensionVersion" XML attribute on the top level "d2LogicalModel" element does calidate against the extended schema but it does not against the full schema:
include optional XML attrbute defintions in section 4.5. alongside "modelBaseVersion"! Modify the tool accordingly! Attributes shouls be made mandatory when creating an extended schema.
The bug is clearly described and the request is appreciated. Since the described proposal may create backwards compatibility issues with existing implementations (whilst the impact of the bug seemingly did not create operational impact so far) it will be addressed in the next major release v3.0.
Include in version 3 in the model.
The model has changed in this area, but the attributes still exist. Assigning as a tool issue for Jonas to confirm it has been resolved in v3.