The URL http://localhost:8080/xwiki/bin/view/Main/DatabaseSearch?xpage=plain&outputSyntax=plain&text=wiki used to work ("view" mode with xpage=plain).
Now it does not. Fortunately the generated URL is http://localhost:8080/xwiki/bin/get/Main/DatabaseSearch?outputSyntax=plain&space=&text=wiki and this URL works ("get" mode used).
However, users could have entered the old URL in their RSS readers, and the link is now broken. So the old URL should work too.