BVPM is a basic package manager. It was written basically to make development of basic-linux easier.
The .bvp file format is just a .tar file (compressed with zstd, although there is not reason that other compression algorithms can't be used since libarchive is used)
The file has two/three extra files in it:
manifest: The package manifest file. Has three entries: name, version and dependencies.
owned-files: The files this package claims. If the package is uninstalled, these will be deleted.
afterinstall.sh: A script thats run at the end of the package installation. Optional.
sums: A list of file hashes. Optional; will give a warning when not present.
A folder called root must be present. The files in there will be copied to the root folder.
BVPM currently has basic repository support. It consists of a single folder, with a repo.manifest file in it. Packages can be added/removed from it with the bvpm-repo utility, which is in the same executable as bvpm, which is simply symlinked.