Depends on D19682. Ref T13202. We currently fatal when trying to render a timeline if:
- an install is fresh, so there are no pages yet, and you look at "/w/"; or
- you're looking at a Phriction page which doesn't exist (yet) like "/w/aadsflknadsflnf/".
Rendering a timeline and comment area doesn't make sense in these cases, so don't render them.