JsPath in RFC 6901 standard

I’m trying to get a JsPath string representation in RFC 6901 standard. It looks like play-json does not support it and I’m not finding a definition of what it uses.

I see that JsPath has specific implementations for toString() and toJsonString(). For example:

import play.api.libs.json._

val jsPath = __ \ "obj" \ "arr" \ 1

val stringPath = jsPath.toString()             // "/obj/arr(1)"
val jsonStringPath = jsPath.toJsonString()     // "obj.obj.arr[1]"

None of these match RFC 6901 of "/obj/arr/1"

Anyone knows if there’s some documentation on what play-json is using and/or how to convert it to RFC 6901?