Boards manager package does not install Sensebender gateway

[billgoolsby]

Using Arduino 1.8.3, I installed the SAMD boards package so I can now choose board = Arduino Zero. Next, since I have the Sensebender gateway board, I inserted the URL for package_mysensors.org_index.json into the Additional Boards Manager URLs in preferences. , as directed on the github.com/mysensors/ArduinoBoards page. However, this doesn't seem to do anything. The list of boards doesn't include any that weren't already there; in particular, the Sensebender gateway is not listed. Is there something else I need to do?