[malte]

On further investigation, I've discovered that in fact it's on a case-by-case basis. Sega Mega Drive and SNES work for example, but Sega CD won't. I'm guessing there is a list somewhere in the code which lists which systems are compatible and just needs updating?

RCB asks RetroPlayer which cores are available for each platform by doing a json request with the RCB platform name as parameter (SNES, Sega Mega Drive, SEGA CD, ...). If RCB does not get a result it assumes that there is no RetroPlayer support for this specifc platform.

I am not sure how RetroPlayer builds this response but I guess that it will check the platform tag in the addon.xml of the libretrocore addons. I just did a short check of the addon.xmls in the repository and I could not find any addon with platform "SEGA CD", so I guess this is the problem.