DOC: Update RPZ file format description
@@ -35,7 +35,9 @@ Currently, different unpackers are maintained: the defaults ones (``directory``
ReproZip Bundle Format (``.rpz``)
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-An ``.rpz`` file is a ``tar.gz`` archive that contains two directories: ``METADATA``, which contains meta-information from *reprozip*, and ``DATA``, which contains the actual files that were packed and that will be unpacked to the target directory for reproducing the experiment.
+An ``.rpz`` file is a ``tar.gz`` archive that contains a directory ``METADATA``, which contains meta-information from *reprozip*, and an archive ``DATA.tar.gz``, which contains the actual files that were packed and that will be unpacked to the target directory for reproducing the experiment.
+
+The ``METADATA/version`` file marks the file as a ReproZip bundle. It always contains the string ``REPROZIP VERSION 2``. It previously contained ``REPROZIP VERSION 1`` before version 0.8 (2015), where ``DATA`` was a directory instead of being a tar.gz file.
The ``METADATA/config.yml`` file is in the same format as the configuration file generated by *reprozip*, but without the ``additional_patterns`` section (at this point, it has already been expanded to the actual list of files while packing).
