That's a Java EE API. I've been working with the Java SE and Java EE folks to make sure that a new version of that will sit on top of the core JDK 9 one.
How did you arrive at the conclusion that a set of interfaces is a JavaEE API?
Above and beyond the fact that in section 2.2 of the JSR it plainly states: "This JSR is targeted for Java SE 6 or higher and Java EE 7 or higher platforms."
We helped test out the RI and TCK - it was in the end up built for Java EE in mind (that's not to say someone couldn't provide a stripped down version that could work for SE - but I don't think anyone has or will).
But it is unclear how many of the existing implementations conform to it, and it definitely doesn't work toward your misguided One True JSON Implementation goal.