Any instance of ReviewBoard may support the FileProvider framework. If they do, they may support different sets of file providers and each one may be implemented differently. By having an API for GET requests, it can lists all of the supported file providers for users and implementations to know what file providers are supported, and information associated with them. GET requests for to learn about individual file providers can also be made with api/file-providers/<name>/

Test cases for the GET api calls (via reviewboard/webapi/tests/test_file_provider.py), and manual testing with GET requests