Expose ability for community to cleanly update / replace XULrunner for XPiNC Merged

XULrunner was chosen to support XPages in Notes Client environment. For many of us, this has enabled a rich, blended development mode with the best of both worlds, while also allowing fully offline use of XPage applications and no secondary dependency on a browser. However, Mozilla stopped updating XULrunner in 2015, and while it's difficult to be certain, it appears that XPages is using a customized release based on the 10.0.x arc; XULrunner development continued far beyond that, with final release being 41.0.2 in 2015. 

If there is no or limited desire from HCL / IBM to maintain or update this core piece of XPiNC, it would be helpful if (1) the current sources were released so the community could do updates / maintenance and (2) it were made possible to cleanly manage the release and distribution to our customers of these releases.