We're migrating to using the cleaner zulip.com domain, which involves
changing all of our links from ReadTheDocs and other places to point
to the cleaner URL.
No change in behavior. The for_you block had already been removed in
portico.html long ago in a6889080ce. The
contents of the block are still present in the non-portico 404.html
and 5xx.html error pages.