By default it creates a time based view to see which persons edited which files and a overview over the files at that point of time.
It does not put the emphasis on the code changes but on the dynamics of the participants.
To generate an overview over the paticipants commits the generated logs were parsed. Sourcecode in this file: https://github.com/educs/Documentation/blob/master/gource/ma...
TL,DR: No code viewing tool.