If there’s no built-in way to customise the path note you can always add a custom release step. You can grab name and version from the given %Mix.Release{} struct.

- steps: [:assemble, :tar],
+ steps: [:assemble, :tar, &rename_tar/1],

# ...

defp rename_tar(release) do
  # ...
  release
end

For future reference, this is what I ended up with:

  defp releases,
    do: [
      market_manager: [
        applications: [
          web_interface: :permanent,
          runtime_tools: :permanent
        ],
        steps: [:assemble, :tar, &rename_tar/1],
        include_executables_for: [:windows]
      ]
    ]

  defp rename_tar(release) do
    tar_folder_path =
      release.path
      |> Path.join("../../")
      |> Path.expand()

    tar_path = Path.join(tar_folder_path, "#{release.name}-#{release.version}.tar.gz")
    new_tar_path = Path.join(tar_folder_path, "application-data.tar.gz")

    case File.rename(tar_path, new_tar_path) do
      :ok -> release
      err -> err
    end
  end

It works like a charm