This was once discussed in the old Ideas repo and addressed in a subsequently postponed draft PR:
Currently, if a single-language site’s default language is other than EN
, plugin UI output is rendered in English even if a suitable translation exists.
While a workaround is possible (in the linked Idea issue), it would still be great if plugins could display their UI texts based on a global locale without the need to override the I18n config on a template basis.