The README should at least mention [Graph Modelling Language](https://en.wikipedia.org/wiki/Graph_Modelling_Language) (GML). There is also [a npm package](https://www.npmjs.com/package/jgf2gml) to convert from JGF to GML. It may also make sense to mention other graph formats such as TGF, GraphML etc. and link to converters where available, e.g. https://www.npmjs.com/package/jgf-dot.