I had the same thought, as an OpenStack developer as well (TBH I don't remember if my username here identifies me or not). Yeah, we can apply as an exceptional case, but realistically us being excluded shows the criteria is very much directed towards "github style" open source.
Maybe worth asking for anyway? They might just be setting metrics based on the most popular ways of measuring but if they care about the spirit of the offer it would make sense for them to be flexible with the letter of the requirements.