Project "Toolkit for sandboxing third-parties libraries in Firefox" described here
https://wiki.mozilla.org/Community:SummerOfCode19

This tracks the progress of writing glue layers between the RLBox API and sandbox type. The RLBox API is an API that allows usage of a sandboxed library in a safe, efficient manner without significantly altering application code. The full description of the API is part of research paper is currently under submission and will be made public after acceptance. Please contact the author for any further details.