Hi Ludo, thanks for your response.
We don't provide them _directly_, but when loading the program the first option is "Load core". Then, first option again, is "Download core". Here you have a list of "proprietary" .so.zip downloads. Retroarch, as far as I understand, is encouraging the download of those programs, with no licensing information (see [1]). I don't know if this is ok or if we can patch it (hiding the "Download core" menu maybe?).
Debian _does_ provide (from their package manager) some o the cores [2], two of them with the non-free tag.
If we patch retroarch to hide the download menu, to make it functional we should also package some free cores.
Thoughts?
Thanks again,
Nicolò