yes that is correct, Oracle is still stackeholding the sourcecode of the Oracle Enterprise Pack for Eclipse OEPE 18.104.22.168 Plugin Tools including the GlassFish Tools 16.3. The current sourcecode is available under the terms of the Eclipse Public License v1.0.
And there the method GlassFishRuntime.createDefaultRuntimeName() only considers the GlassFish Server Versions 4 and 3.1.
In a discussion about OEPE for Eclipse Oxygen at https://community.oracle.com/thread/4060271, "KostaOracle" stated on 29.09.2017 "An OEPE version that's compatible with Eclipse Oxygen is undergoing final testing and will be released soon."
But there is no information about a roadmap, new features in paticular Java EE 8 or GlassFish 5.
And when clicking on Release Notes of Version 22.214.171.124, a website of an older OEPE Version appears.
Maybe the Oracle Corporation should agree to push the sourcecode to GitHub and extend the content in a collaborative effort.
But the problem will be, that OEPE also contains other features for WebLogic, MAF, ADF, etc.
So there should be a seperated Plugin under a new name, maybe something like EE4J-Plugin.
But how fast could we have a "OK->GO" from the Oracle Corporation?