This extension was developed as part of the jsonapi module for Drupal.
It is possible for a server to have mixed success and error responses when dealing with a single or multiple entities at once. For instance, when generating collections of resource entities there is a chance that the GET operation results in a partial success. That is because each entity can generate errors independently from the other. In such scenarios the server MAY respond to the request with a partial success response.
Servers and clients MUST negotiate support for and use of the Partial Success extension as described in the base specification using
partialsuccess as the name of the extension.