The files ending in .tar.xz are the binary packages.
The files ending in .tar.xz.sig or .tar.xz.asc are detached PGP signatures, in different formats.
The file make-usr-local.zsh is a Zshell script that was used to create the packages. To use it requires an already-working /usr/local and assumes my /usr/local/share/config.site file. No great care was put into its neatness or modularity. It is included here as a primitive example of how to make a package. (I use envfs, and so the #!/bin/zsh shebang works.)