> I mean the information in the ROM. The game itself.
Almost certainly the publisher. Same goes with any book or album. Ever see "lyrics reproduced with permission" on the sleeve note? It's because the record company owns them, in the same way that a publisher owns the code of games it publishes, unless ownership rights were somehow reserved in the contract (but the developer would have to be in a pretty strong negotiating position to manage that - maybe someone like Peter Molyneux could get away with it).
As for the license-holder (eg Nintendo, etc), so far as I understand, that's more to do with rights and permissions to have games released on any given system, sometimes exclusively. It's not at all related to ownership rights for the intellectual property.
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