> Doesn't XeTeX contain libraries which are under GPL too? Kpathsea,
Kpathsea is under lgplv2.1 or later.
Whether xetex contains any gpl'd code (e.g., from pdftex), I don't know,
but I wouldn't rule it out.
http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=xetex_download
As Reinhard replied, that's for the code that Jonathan wrote.
karl