Improve current client error 404/403 pages
Open, Needs TriagePublic

Description

Thinking about it, we could do with a better 404 and 403 error page.

Error pages are almost wasted talent, as we don't really want people to see them, but alas, sometimes they do, and they shouldn't be terrible.

This will also need translation in the languages that we can do before a new 403/404 page is deployed since we have a multilingual audience.

While having this page available in as many languages would be nice, I'm not really sure if it's feasible.

It means we then need to develop a way for the community to provide translations and find a way to manage exporting those back to the error pages. By their nature, they are likely to be flat HTML, and then we have to do lots of funky magic working with languages in headers, which may rely on things we don't have available. Alternatively, we could display English and link off to all the other languages as HTML files/hidden "sections" with JS?