Yes, that is no longer made, and has been discussed on the lists before.
The way that page was generated is by running a script in the ports tree, namely:
ports/infrastructure/package/gen-package-pages
You may be able to generate a local list with that, use an FTP/HTTP client to browse the package directory, or preferably use
http://openports.se/.
On that site, when you search for a port,
www/mozilla-firefox, it'll show you the package name near the top that you can use with the pkg_* tools.
Remember to exclude the version number, as that site tracks -CURRENT.