While le-tex has been using GNU make for process automation for years, they increasingly employ XProc pipelines for sophisticated XML-related conversion/checking processes.

XProc, besides XSLT 2.0, serves as the technological foundation for the open source XML conversion/checking framework le-tex transpect.

Apart from transpect, le-tex provides extensions to the XProc processor XML Calabash such as an image data extractor, and there is a tool for modifying .docx files. All these tools are made available as open source software, using the permissive 2-clause BSD license.