It seems that user names are exposed outside domain - e.g non-Wikimedia sites.
This is privacy concern: editors in Wikipedia may not want to share other sites that they are editors and their user names in Wikipedia.
Example:
- login to Wikipedia
- go to http://randomfax.net/wiki/
- wait for page load
- your username is shown in the top.
Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=55887