We should create a new repository for our error pages, MissingWiki.php and 404.php.
This would allow localisation of them similarly to how we localise the landing page.
Assigning to myself as I will do the work to create the repository, and move them over, and then localise them, as long as there are no objections to doing this.
Alternatively we could simply move them to landing, but that isn't ideal because they wouldn't exactly fit in there. The best option, in my opinion is a new repository.