Board Thread:Ask the Staff/@comment-26468465-20160326133630/@comment-28857181-20160326135716

From personal experience, I do not know of any but I do know that some users have their own little "secret" pages where they work on stuff like if I go to User:DaniSkies/Sandbox, I can just test out some stuff (that's basically the idea of my /Avatars and /Sigs pages to choose from and look back at later). However, that's private and not open to the public.

In contrast, I believe there's a public sandbox wiki where anyone can test coding, java, themes, stuff like that. Of course, we could easily make a sandbox if it's something we think we need.