Comment # 3 on bug 1112817 from Wolfgang Rosenauer

(In reply to Frank Kruger from comment #2)
> (In reply to Wolfgang Rosenauer from comment #0)
> > Firefox 63.0 as to be released 2018-10-23 requires rust >= 1.28 to build.
> > Tumbleweed's current rust version is 1.26.2 only.
> 
> Does this, in turn, mean that there won't be any Firefox 63 for Leap 15.0
> through the mozilla repo?

Yes, it's currently not possible to build Firefox 63 on openSUSE any openSUSE
distribution in OBS.
As soon as rust 1.28 is in devel:languages the mozilla repo will utilize it and
I can provide FF63 for older Leap versions.