Lines 38 and 2038 (section 3.2.1.2) define a repositoryURI as a required attribute of a repository. However, the usage of the URI (what it points at, how one might navigate it, etc) are not stated. What is the point of having something required without any guidance as to how a client might use it? That simply makes it repository-specific. This parameter should be removed, or made optional (with a statement that a repo can fill in some repo-specific uri here or whatever).
OR? Is the URI to be used as an identifier (probably not, as the repositoryId seems to want this task).