The SDG Sandbox creates a space for the review of data models produced by WP4 - Data semantics, formats and quality - in the context of the preparatory work for the Single Digital Gateway Regulation.
Indeed, TTL stands for Turtle, a broadly used syntax to express RDF statements. Depending on the needs, we can of course also provide alternative formats.
Several of the README.md files mention "TTL". What is meant with that?
I guess that it might mean Turtle, but I am not certain: https://www.w3.org/TR/turtle/