Jpackage (JEP 343) was initially implemented as incubator module in JDK14, and again in JDK15. The intent is to make it non-incubator (finalized) in a future release.
This is the implementation JEP 392: Packaging Tool (JDK-8247768), reverting jpackage from the jdk.incubator.jpackage module to the jdk.jpackage module, fixing any related tests, make files, and other dependencies.