Is docbook.transform() code you wrote to run the Docbook stylesheets?

Got it now, it is (probably) what xsltc compiles docbook.xsl to. Have
tried to identify what exactly fails there but I am lost, there is too
much going on in the docbook stylesheets with all the imports/includes.
I guess at docbook.l10n$dot$language() points at the language template
in l10n.xsl but I can't tell why the xsltc engine can't handle that.