The first tests with the next version of the Apple operating system macOS 10.13 are already beginning to be carried out on the network. This is usually something normal a few months before the WWDC that is held in June, and is beginning to show on the network and is indicative that Apple will not leave loose ends in the presentation of the operating system and subsequent launch. Remember that the developer versions of the different operating systems are released during the same WWDC on June 5 and in this case the first sign that the system is already working is evident with this URL.
It is usually common to see these traces during the weeks before WWDC, but in this case we believe that it is really early to see the first "traces" of this new version that Cook and his team will present to us in what is supposed to be the second keynote of the year (if we are confident that March will be the first) and that it will later be released for developers. In this case the full url is as follows: https://swscan.apple.com/content/catalogs/others/index-10.13seed.merged-1.sucatalog.gz -appears to be an HTTPS link coming from Apple's servers-
Some media such as MacRumors also add their own graph with the navigation made with this new version of the Apple operating system macOS 10.13 and we see that since last year they have already received visits from this version, but the increase at the beginning of this 2017 is quite remarkable. Another detail is the list of names that they publish could use this new version of the operating system: Redwood, Mammoth, California, Big Sur, Pacific, Diablo, Miramar, Rincón, Redtail, Condor, Grizzly, Farallón, Tiburon, Monterey, Skyline, Shasta, Mojave, Sequoia, Ventura, and Sonoma. Curious to say the least. We will wait to see if more details of this new version of macOS appear leaked on the network.