As Bill says, we now have a staging server. Chris also added a cool feature that automatically generates the site when a PR is updated.
Since the feature has only just be installed, it only manifests when a new PR is created or an old one is updated. In these cases, you'll see a check labeled "netlify/jakartaee-specifications/production Production deploy ready!"; when you click on "details", it will take you to a rendering of the website with that PR's content rolled in.
Note that I noticed that the breadcrumbs are rendered with absolute URLs; clicking on an entry will take you to the production site.
FWIW, the production site is operating as designed and as I described. That some of the specifications were rendering was due to the value in the date field being in the past. When I changed them to September 10/2019, they were removed on the next deployment. I believe that there was some consensus that we wanted to keep information about specifications off the production site until after they were released. Based on this experience, we may want to change this.
I envision that that the metadata at the top of each of the specification files will be valuable (and possibly expanded at one point); we might, for example, generate some kind of data file out of these files. So, having a real date of release here feels like something we want to have. Hugo actually uses the "date" (and "publishDate") fields. We could instead create our own "releaseDate" field and either put a different value in the date field, or just remove the date from the header and render additions as they come (regardless of release date).
I'm thinking that this may be a topic for our retrospective.
Wayne