When searching for the xsl for rendering a content type, extends are not used.

In my use-case, I have content-type A, B and C which all extend ZZZ (which is abstract)

I want an export, filtering on content-type ZZZ, that will return contents of types A, B and C

For the rendering, I only specified an xsl for ZZZ, but the default-content2export-doc.xsl is used instead of ZZZ2export-doc.xsl, so now I have to create xsl for each one of my content-types, that just import the parent xsl.

It could be usefull to handle this when the export uses a content type (use the content's content-type, then go up untill we reach the one used in the export, and then only, use the default)