config uri
In most cases this is simply an absolute or relative path to a config file on the system. However, it can also be a RFC 1738-style string pointing at a remote service or a specific parser without relying on the file extension. For example, my-ini://foo.ini may point to a loader named my-ini that can parse the relative foo.ini file.
An object conforming to the plaster.ILoader interface. A loader is responsible for locating and parsing the underlying configuration format for the given config uri.
loader protocol
A loader may implement zero or more custom named protocols. An example would be the wsgi protocol which requires that a loader implement certain methods like wsgi_app = get_wsgi_app(name=None, defaults=None).