Release notes [1]:

> Release notes for 4.12.2
> ========================
> - Feature: Support for RandR's 'primary monitor'
> - Translation updates: Arabic, Asturian, Basque, Bengali, Bulgarian,
>   Catalan, Chinese (China), Chinese (Hong Kong), Chinese (Taiwan),
>   Croatian, Czech, Danish, Dutch (Flemish), English (Australia),
>   English (Great Britain), Estonian, Finnish, French, Galician,
>   German, Greek, Hebrew, Hungarian, Icelandic, Indonesian,
>   Italian, Japanese, Kazakh, Korean, Lithuanian, Malay,
>   Norwegian Bokmål, Norwegian Nynorsk, Occitan, Panjabi, Polish,
>   Portuguese, Portuguese (Brazilian), Romanian, Russian, Serbian,
>   Slovak, Slovenian, Spanish, Swedish, Telugu, Thai,
>   Turkish, Ukrainian, Uyghur, Vietnamese

[1] https://mail.xfce.org/pipermail/xfce-announce/2017-December/000564.html