YUICompressor is still packaging modified Rhino files, see also https://github.com/yui/yuicompressor/tree/v2.4.8/src/org/mozilla/javascript , and it still has a dependency on Rhino (1.7R2), which means the problem from XWIKI-6148 that made us use a custom jar of YUICompressor is still present.

But, at the same time, we're not using YUICompressor for JavaScript minification for some time (been replaced by Closure Compiler). We're using it only for CSS minification. So maybe the problem described in XWIKI-6148 is not relevant anymore, assuming that the modified Rhino files are used only for JavaScript minification.