It looks to be a custom function for parsing JSON arrays: https://github.com/haifengl/smile/blob/5bf4075b2978af68b31c77f678de167a3e8a9036/json/src/main/scala/sm

It looks to be a custom function for parsing JSON arrays: https://github.com/haifengl/smile/blob/5bf4075b2978af68b31c77f678de167a3e8a9036/json/src/main/scala/smile/json/package.scala#L45 https://github.com/haifengl/smile/blob/5bf4075b2978af68b31c7... The benefit is that the type will be known to be JSArray without need for runtime casting (at least, outside the scope of the function). For comparison, `json` returns a JSObject. I honestly haven't seen this before working with Scala, and it's defined just for the smile repository.