This add-on is only compatible with OH 2.5. Last I looked and have mentioned a couple times in the forum, Jython 2.7.2 or newer is required for OH 3.0. I haven’t put much time into it, but manual installations of Jython and other languages are not working in OH 3.0, so it appears add-ons for ScriptEngineFactories may be required for OH 3.0. This could possibly be due to PRs that were merged even after I had specifically asked for them not be merged until after I had reviewed and tested them.
I had originally submitted a Jython PR nearly a year ago, before the OH 2.5.0 release, but the maintainers chose to ignore the submission and then not make any effort to include it in the release. Since then, the OH maintainers have chosen to ignore or block my automation development efforts (read through the PRs in the OP), so these PRs will not be included in any openHAB release. Don’t fret though… after finishing up some updates to the helper libraries, I will provide an update to this add-on. This will allow everyone to use add-ons to install the latest helper libraries and Jython 2.7.2 with OH 2.5.x. As for post OH 2.5.x, 