These rules have been extracted from the Bazel sources and are now available at bazelbuild/rules_pkg (docs).
Issues and PRs against the built-in versions of these rules will no longer be addressed. This page will exist for reference until the code is removed from Bazel.
For more information, follow issue 8857
pkg_tar() is available for building a .tar file without depending on anything besides Bazel. Since this feature is deprecated and will eventually be removed from Bazel, you should migrate to @rules_pkg.