Somehow I led us astray.

I thought the xs:appinfo source attribute used by DFDL should be the same as the DFDL namespace URL, but that's not the case.

I even put a check in which issues a warning if one uses http://www.ogf.org/dfdl/ and not the namespace URL.

This is wrong.

Section 6.1 of the spec clearly states:

The xs:appinfo source URI http://www.ogf.org/dfdl/ is used to distinguish DFDL annotations from other annotations.

So we need to change to use that URL uniformly everywhere. We can make the code tolerant of the namespace URL or the correct source attribute value, but we should globally replace where we have it wrong.