There is no link directly to updateCenter.

If one installs a plugin/updates Hudson to a newer version, they are forwarded to /updateCenter page where
they can trigger a safe restart to Hudson. But if someone leaves this page for some reason, they can not go back,
and the button "Safe restart" is nowhere to be found.

Well, actually, it can be found, if one manually links the browser to /updateCenter, which is really a hack and an annoyance.

So why not provide a link to /updateCenter from the /manage screen?