Basics needed for running RC in Intellij

[SiWoC]

Hello,
I have forked the github repo, cloned it and imported the pom in a fresh Intellij installation.
I can run what I think is the main-class slash.navigation.converter.gui.RouteConverterOpenSource
This starts the GUI in offline mode showing "RouteConverter OpenSource Edition ? from ?"
But it shows no map.

In the logging I see the downloadmanager complaining about "outdated" files.

Do I need to configure something extra? Tweak a config in a resources-folder? Get my own api-keys? Tweak config in the users/.routeconverter folder?
Can I run the RouteConverterWindowsBundle.exe alongside this developer-edition? Or might they interfere with eachothers config?

[SiWoC]

So I created the CoPilot10Format.class, but am a bit stuck testing this while the map-tiles are not showing.
Any pointers anyone?