The URL for the official PLDB site is https://pldb.com. DNS will take that domain name and send your browser an IPv4 address. Your browser will send a request to that address which will reach our virtual server running Nginx (nicknamed Marconi) running in a Digital Ocean datacenter. Marconi will send you the HTML, CSS, Javascript, PNGs, SVGs and JSON that make up the built website.
In case there's a problem with Marconi, you should be able to access the exact same site served from GitHub's servers here: https://github.pldb.com.
If Marconi AND GitHub were to go down at the same time...well that's why it's good to regularly download the entire source code of the site to your own machine! You can do that with:
git clone https://github.com/breck7/pldb.git
# Then to keep it updated:
cd pldb
git pull
We have another server running at Digital Ocean named Build that serves build.pldb.com. Build serves the site and also let's you easily edit the database right in your web browser. If Build is at all flakey, it's recommended you just submit your changes to the PLDB repo using the normal GitHub UI.