I have a quote from Kai:
As a result of those activities, the current 3.0.0 code base is not yet usable, so please refrain from trying out any 3.0.0-SNAPSHOT distro for the moment. It anyhow [does not include any add-ons ](https://github.com/openhab/openhab-addons/pull/6701), so it is rather pointless.
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The question is: what are you trying to do, 3.0 is NOT even close to be released!