Hey there
Translations are stored in tables, not cached per se.
If you have data explorer, you may use a query like such to view the stored translations (there are topic_localizations, post_localizations, category_localizations, replace accordingly).
select * from topic_localizations
limit 10
Discourse uses terms like topics, posts, and such (this might be useful). A topic has a title and has posts. This reply itself is a post. We do not store just one translation per full topic. So for example in this topic we have:
- topic translation for the topic title
- post translation for your post above
- post translation for my post now
- (post translation for any subsequent post)
Hope this helps.