[Wintermute0110]

definitely. i'm sure that's being taken into consideration - the archive.org rom add-on has been working with retroplayer for a while i know so there should be lines of communication open already. afaik for now it's integrated in the 'other' way around - you use your add-on just as before, but instead of launching an external emu it launches with the internal ones.

All good. Currently AEL does not support Retroplayer. Is there any piece of documentation about how to use it? Also, can a Python plugin get a list of installed cores so user can choose which one to use a launcher?

[ironic_monkey]

i think that bit is up to the kodi core right now, you launch the rom like you would launch any other media, and if there are multiples you get a menu like you get with 'play using..', with an option to set defaults to avoid the menu. i don't think it makes sense to leave it up to add-ons to handle the player selection stuff.

wait for garbear to comment though, this is just a somewhat-educated guess.