fresco is a library to enable multi-language, multi-paradigm programming. It consists of multiple components, handling different areas. There is a runtime for threading and interface topics (intonaco), a toolset to provide some data sttructure and tooling around it (sinopia) and a tool for running multiple components together and finding dependencies (arriccio).
The naming is originating in the fresco techniques, the intonaco is the last fresh layer of plaster, which intermix with the colour pigments, the sinophia is a first scetch of the final picture in monochrome paint.
The single components have their own documentation (or at least some explanations):