And why would anyone take his time for open source ANEs exactly?
20$ would not even pay half an hour of my time, so that would be quite the uneconomical waste.
There is currently no ANE for ad networks besides Distriqts with Admob. I'm in contact with IronSrc and Ogury, both are very reluctant to change that state, even though we earn them quite a lot of money. But that is Harmans fault as their first step should've been to make a public website with clear public licensing 4 months ago.