Create an alternative to webkit that is used everywhere as it release bindings to many languages.
I tried in the past with a FFOS emulator: https://discourse.mozilla.org/t/g-ene-one-day-experiment-gecko-alternative-to-electron-nw-js/7106
But mozilla tried years ago with positron: https://github.com/mozilla/positron
Maybe today with Servo it is possible and avoid to use Gecko that is so integrate in Firefox that is idficult to separate it