Thank you for hints!
I have found your json from Nov`17
I copied the file and defined the link to it in eBUS Configuration binding (paper UI)
///etc/openhab2/eBUS/VR61_Witek.json (I named the file with you nick/name😊)
Also I have tried with the file I have found on GitHub and defined as follows
///etc/openhab2/eBUS/V6100.50.v61.mc_configuration.json in eBUS Configuration
But in both cases no additional commands for HC2 appeared in papaer UI and I have the following error (example for V6100.50.v61.mc_configuration.json) :
2020-05-07 22:48:48.418 [ERROR] [internal.things.EBusTypeProviderImpl] - Error on loading configuration by url: no protocol: ///etc/openhab2/eBUS/V6100.50.v61.mc_configuration.json
2020-05-07 22:48:48.483 [WARN ] [internal.things.EBusTypeProviderImpl] - eBUS command boiler.control.setopdata only contains a setter channel!
Seems like some sort of a basic error while I am trying to add json? 
Shall I do something else in the set up?