The project page for spaces links to API.txt and README.txt under documentation. These both point to the old CVS browser interface. Correct links should be:

API - http://drupalcode.org/project/spaces.git/blob_plain/refs/heads/6.x-3.x:/...
README - http://drupalcode.org/project/spaces.git/blob_plain/refs/heads/6.x-3.x:/...