While they were much too verbose, the current filenames don't give some critical information about the binaries they contain.
One missing point is the OS version. For all of Ubuntu, macOS and Windows, the binaries are built for some particular version, and there is the hope they will run on higher versions. It is quite likely they won't run on earlier versions. As a trivial example, the Windows version likely won't run on XP, or NT. The choice of build target is reasonable, but it should be labeled. The second point, for macOS only as the rest are labeled, is the CPU architecture of the binaries. Right now it's x86_64 (because that's what github provides). While it's true that M1/aarch64 computers can run those via emulation, lots of things can emulate lots of things, and it should be clear what's in the tarball, with reasoning about "I can run a binary built forfor macOS 10.15 x86_64 on my macOS 13 aarch64 computer." being separate. (An example of why emulation is complicated is that NetBSD/amd64 can run NetBSD/i386 binaries and also most Linux/x86_64 binaries. This is outside the scope of Unison.)