Print of `revisions` at this line
https://forge.softwareheritage.org/source/swh-storage/browse/master/swh/storage/storage.py$692

[{'author': {'email': 'robot@softwareheritage.org',
             'fullname': 'Software Heritage',
             'name': 'Software Heritage'},
  'committer': {'email': 'robot@softwareheritage.org',
                'fullname': 'Software Heritage',
                'name': 'Software Heritage'},
  'committer_date': {'negative_utc': False,
                     'offset': 0,
                     'timestamp': {'microseconds': 0, 'seconds': 944729610}},
  'date': {'negative_utc': False,
           'offset': 0,
           'timestamp': {'microseconds': 0, 'seconds': 944729610}},
  'directory': ':\xeb\xc2\x9e\xd1\xfc\xccJo/ \x10\xfb\x8eW\x88$\x06\xb5(',
  'id': 'D\x184\x88\xc0wL\xe3\xc9W\xfa\x19\xbai\\\xf1\x8aJB\xb3',
  'message': 'swh-loader-package: synthetic revision message',
  'metadata': {'package': {'archive': 'https://ftp.gnu.org/gnu/8sync/8sync-0.1.0.tar.gz',
                           'date': '944729610',
                           'id': 'D\x184\x88\xc0wL\xe3\xc9W\xfa\x19\xbai\\\xf1\x8aJB\xb3'}},
  'parents': [],
  'synthetic': True,
  'type': 'tar'},
 {'author': {'email': 'robot@softwareheritage.org',
             'fullname': 'Software Heritage',
             'name': 'Software Heritage'},
  'committer': {'email': 'robot@softwareheritage.org',
                'fullname': 'Software Heritage',
                'name': 'Software Heritage'},
  'committer_date': {'negative_utc': False,
                     'offset': 0,
                     'timestamp': {'microseconds': 0, 'seconds': 947003574}},
  'date': {'negative_utc': False,
           'offset': 0,
           'timestamp': {'microseconds': 0, 'seconds': 947003574}},
  'directory': 'F\xd8\xb4\xd6\xeb\xc1rAk\xee\xea\x9c\xd9\x1fq\x00r\xd9\x1e\xe3',
  'id': '\xc57\xd4\xad\xbeM\xc0\x01\xb0G\xeb\xb2\xce\xa4\x15I\x84w\x13\x84',
  'message': 'swh-loader-package: synthetic revision message',
  'metadata': {'package': {'archive': 'https://ftp.gnu.org/gnu/8sync/8sync-0.2.0.tar.gz',
                           'date': '947003574',
                           'id': '\xc57\xd4\xad\xbeM\xc0\x01\xb0G\xeb\xb2\xce\xa4\x15I\x84w\x13\x84'}},
  'parents': [],
  'synthetic': True,
  'type': 'tar'}]


print of contents of `revisions_filtered` here 
https://forge.softwareheritage.org/source/swh-storage/browse/master/swh/storage/storage.py$710

{'author_email': 'robot@softwareheritage.org',
 'author_fullname': 'Software Heritage',
 'author_name': 'Software Heritage',
 'committer_date': '1999-12-09T08:53:30+00:00',
 'committer_date_neg_utc_offset': False,
 'committer_date_offset': 0,
 'committer_email': 'robot@softwareheritage.org',
 'committer_fullname': 'Software Heritage',
 'committer_name': 'Software Heritage',
 'date': '1999-12-09T08:53:30+00:00',
 'date_neg_utc_offset': False,
 'date_offset': 0,
 'directory': ':\xeb\xc2\x9e\xd1\xfc\xccJo/ \x10\xfb\x8eW\x88$\x06\xb5(',
 'id': 'D\x184\x88\xc0wL\xe3\xc9W\xfa\x19\xbai\\\xf1\x8aJB\xb3',
 'message': 'swh-loader-package: synthetic revision message',
 'metadata': {'package': {'archive': 'https://ftp.gnu.org/gnu/8sync/8sync-0.1.0.tar.gz',
                          'date': '944729610',
                          'id': 'D\x184\x88\xc0wL\xe3\xc9W\xfa\x19\xbai\\\xf1\x8aJB\xb3'}},
 'parents': [],
 'synthetic': True,
 'type': 'tar'}

{'author_email': 'robot@softwareheritage.org',
 'author_fullname': 'Software Heritage',
 'author_name': 'Software Heritage',
 'committer_date': '2000-01-04T16:32:54+00:00',
 'committer_date_neg_utc_offset': False,
 'committer_date_offset': 0,
 'committer_email': 'robot@softwareheritage.org',
 'committer_fullname': 'Software Heritage',
 'committer_name': 'Software Heritage',
 'date': '2000-01-04T16:32:54+00:00',
 'date_neg_utc_offset': False,
 'date_offset': 0,
 'directory': 'F\xd8\xb4\xd6\xeb\xc1rAk\xee\xea\x9c\xd9\x1fq\x00r\xd9\x1e\xe3',
 'id': '\xc57\xd4\xad\xbeM\xc0\x01\xb0G\xeb\xb2\xce\xa4\x15I\x84w\x13\x84',
 'message': 'swh-loader-package: synthetic revision message',
 'metadata': {'package': {'archive': 'https://ftp.gnu.org/gnu/8sync/8sync-0.2.0.tar.gz',
                          'date': '947003574',
                          'id': '\xc57\xd4\xad\xbeM\xc0\x01\xb0G\xeb\xb2\xce\xa4\x15I\x84w\x13\x84'}},
 'parents': [],
 'synthetic': True,
 'type': 'tar'}



Revision value in the When printed in the `fetch_data` of GNU Loader 


{'author': {'email': b'robot@softwareheritage.org',
            'fullname': b'Software Heritage',
            'name': b'Software Heritage'},
 'committer': {'email': b'robot@softwareheritage.org',
               'fullname': b'Software Heritage',
               'name': b'Software Heritage'},
 'committer_date': {'negative_utc': False,
                    'offset': 0,
                    'timestamp': {'microseconds': 0, 'seconds': 944729610}},
 'date': {'negative_utc': False,
          'offset': 0,
          'timestamp': {'microseconds': 0, 'seconds': 944729610}},
 'directory': b':\xeb\xc2\x9e\xd1\xfc\xccJo/ \x10\xfb\x8eW\x88$\x06\xb5(',
 'id': b'D\x184\x88\xc0wL\xe3\xc9W\xfa\x19\xbai\\\xf1\x8aJB\xb3',
 'message': b'swh-loader-package: synthetic revision message',
 'metadata': {'package': {'archive': 'https://ftp.gnu.org/gnu/8sync/8sync-0.1.0.tar.gz',
                          'date': '944729610'}},
 'parents': [],
 'synthetic': True,
 'type': 'tar'}
{'author': {'email': b'robot@softwareheritage.org',
            'fullname': b'Software Heritage',
            'name': b'Software Heritage'},
 'committer': {'email': b'robot@softwareheritage.org',
               'fullname': b'Software Heritage',
               'name': b'Software Heritage'},
 'committer_date': {'negative_utc': False,
                    'offset': 0,
                    'timestamp': {'microseconds': 0, 'seconds': 944729610}},
 'date': {'negative_utc': False,
          'offset': 0,
          'timestamp': {'microseconds': 0, 'seconds': 944729610}},
 'directory': b':\xeb\xc2\x9e\xd1\xfc\xccJo/ \x10\xfb\x8eW\x88$\x06\xb5(',
 'id': b'D\x184\x88\xc0wL\xe3\xc9W\xfa\x19\xbai\\\xf1\x8aJB\xb3',
 'message': b'swh-loader-package: synthetic revision message',
 'metadata': {'package': {'archive': 'https://ftp.gnu.org/gnu/8sync/8sync-0.1.0.tar.gz',
                          'date': '944729610'}},
 'parents': [],
 'synthetic': True,
 'type': 'tar'}



For reference NPM revision

{'author': {'email': None,
            'fullname': b'Goldeneye Solutions',
            'name': b'Goldeneye Solutions'},
 'committer': {'email': None,
               'fullname': b'Goldeneye Solutions',
               'name': b'Goldeneye Solutions'},
 'committer_date': {'negative_utc': False,
                    'offset': 0,
                    'timestamp': {'microseconds': 0, 'seconds': 1396886527}},
 'date': {'negative_utc': False,
          'offset': 0,
          'timestamp': {'microseconds': 0, 'seconds': 1396886527}},
 'directory': b'\xec\x08\xa3\x05\x8fM9?\x81\x0eE!+\x9c\xfa\n8\xe8\xc3y',
 'id': b'm\xd5@6\xaa*v\xa6A\x8c\xfb\xc5Zk\x9eW\xa8\xb2lU',
 'message': b'0.0.1',
 'metadata': {'package': {'author': 'Goldeneye Solutions',
                          'copyright': '© 2014 Goldeneye Solutions Inc.',
                          'dependencies': {'ja-lib': '0.1.x'},
                          'description': 'Compose a cross-platform application '
                                         'from various things.',
                          'engines': {'node': '>=0.9.9'},
                          'name': 'ja',
                          'version': '0.0.1'},
              'package_source': {'blake2s256': 'fcf5438822e12c8a6973b9ecb40df4978947edd675c4269d728d5279dc82b203',
                                 'date': '2014-04-07T16:02:07.453Z',
                                 'filename': 'ja-0.0.1.tgz',
                                 'name': 'ja',
                                 'sha1': '31399c51d3024f6eb91c626a31a175dc30f343e5',
                                 'sha256': '8101e284d5846e77f9698628da660e92f8627535c266a3aef28549b25e63a597',
                                 'url': 'https://registry.npmjs.org/ja/-/ja-0.0.1.tgz',
                                 'version': '0.0.1'}},
 'parents': [],
 'synthetic': True,
 'type': 'tar'}