Comment 1 for bug 944670

Available regions should be all countries from ISO-3166.
We're going to use the 2-letter codes, so for example "blacklist-iso3166::us" would make an app unavailable for purchase in the US.

The developer should be able to select which regions are blacklisted. Probably the same screen where hardware requirements are selected would make sense for this.

It might be interesting to restrict the number of blacklisted countries to something reasonable like 100 countries, so that you can't select a huge number of debtags for your app

Also consider bug #1006570 when you implement this.