Thanks, looks good so far. I would require them to be licensed under the terms of the "GPLv3 or later" (or a compatible/more permissive license, e.g. public domain also works) if I am to include it directly in the gPodder distribution - it would make my life much easier

Of course you will be mentioned in the contributors list if your icons are added to gPodder (except if you explicitly don't want to be mentioned ). And no, I did not have time to integrate them yet - I'm waiting for some more feedback and will probably decide if/how/where this is going to be added next week or in Barcelona.