I just hit an issue on a package that depended on this one with a collision in case-sensitivity on resource folders/copying. ru-ru is not technically the standard for ICU/ISO naming standard but instead should be ru-RU

Ref: https://unicode-org.github.io/icu/userguide/locale/#country-code
Relevant snippet

To allow for these differences among specific geographical, political, or cultural regions, 
locales are specified by two-letter, uppercase codes.