In #2275865: Per language settings (vs translated settings) are not directly supported I just learned that we do not have translatable variables in core. Variable module has provided these functionality we used in many modules. I tried to abuse core in #2276343: Re-implement per language settings in D8 and rolled back later after Garbor told be about some problems.

What are the plans for D8 with variable module? Will it fill these gap? I guess core will not, but I could be wrong...