This is DGS, short for Document Generation System (pronounced ['degeʃ]).
DGS is a build system for structured documents, mostly those built on standardized frameworks, where the structure is always the same (or very similar) but the underlying data change -- such as correspondence seminar problems, competitions, lectures, lectures and handouts. It includes a basic support for internationalization.
The same content can be repeatedly rendered to various templates or output formats,
for instance XeLaTeX for printable documents and HTML for the web.
DGS is built with Makefile, Python and XeLaTeX, and uses pandoc and rsvg-convert
to process content.