tiddlyweb.usersign is a member of the environ value that is passed around all the WSGI code in TiddlyWeb. It contains information about the current user as determined by the credentials extractor system. The data is passed to a policy when it is checked.

There are two elements in the data structure:

• name: A string representing the identity of the current user. If no user was extracted this will be GUEST. It should never be empty.
  
• roles: A list of strings of roles. This may be a zero length list.
  
  

The name usersign is used because there's nothing preventing the user from having an identifier which bears no resemblance to a name.