I just notice that when you go to the different Drupal Translations sites (for example the French site) there is a user named Multiple contributors but I can't figure out what this means, is a user or a contribution that is made from a different site?
See the Working with translation files offline documentation under the Contributing back to the community header:
When you have finished, contribute the translation back to localize.drupal.org by importing the file on the translation team user interface. Translations will either be attributed to you or "Multiple contributors" depending on which option you choose. "Multiple contributors" is a special account you can use if multiple people worked on the translations being imported and singling out one contributor for attribution would not be correct.
