I was eagerly awaiting the latest version of BorgBackup in Leap 16.0::
https://forums.opensuse.org/t/why-is-borgbackup-in-leap-15-6-so-old/181419/4
However, it now appears that BorgBackup is completely missing from the Leap 16.0 release:
https://software.opensuse.org/package/borgbackup?locale=en
It seems my only option to get an up-to-date version may be to switch to Tumbleweed.
Does anyone have any other ideas or suggestions on how to resolve this issue?
Do not use s.o.o to search for packages. It is broken since years.
borgbackup is available for Leap 16. Simply install it via zypper or Myrlyn.
sudo zypper in borgbackup
Always use internal tools like Myrlyn or zypper for software search first! Only then if you don’t find packages via the internal tools and already configured repos, you should use external search tools and repos.
I’m still running an older version and haven’t migrated to Leap 16.0 yet. Before performing the upgrade, I would like to determine the exact package list and versions available in the Leap 16.0 repositories. What is the recommended method to check this information remotely without having to install the new version?
Have a look at the repo…
https://download.opensuse.org/distribution/leap/16.0/repo/oss/
https://download.opensuse.org/distribution/leap/16.0/repo/oss/noarch/
https://download.opensuse.org/distribution/leap/16.0/repo/oss/x86_64/
It has a search field in the upper right, so you can easily search for the package name and see the available version.
Thanks, that was too easy 
Any ideas why? Are there plans to actually fix it or if not, get rid of it?
Assuming this is a genuine question and not just keeping up the conversation …
Search on s.o.o is just a frontend to the internal search functionality of Open Build Service on build.opensuse.org. OBS was never intended as a tool for publishing distributions and it simply does not have the information to answer the question “which openSUSE releases include this package”. It shows OBS projects containing the package in question. As long as each openSUSE release was built in the own separate project it sort of worked. But now Leap releases are assembled from multiple projects, some of them being hosted on the internal SUSE build platform, so the assumption “one release - one project” falls apart.
It does not need plans. It needs someone doing the work.
The problem can be fixed either by extending the backend (OBS) to provide the necessary information or by changing the frontend on s.o.o. The former is unrealistic. The most straightforward way to do the latter is to parse the repository metadata, not the OBS search results. That is exactly what the web site that once existed (webpinstant.com) did. The sources for s.o.o are not secret:
Absolutely it was. Someone passing by, who isn’t privy to all the background and history, and sees a comment like “don’t use s.o.o, it’s been broken for years”… it begs the question of ‘why’ and ‘when is it getting fixed’ or if not, ‘when is it going away’.
Thank you for the detailed reply.