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I saw at the SO site some icons for the tags (like asp.net-mvc).
May be we can add country flags for its badge? It will add some colors to tags and questions will be easy to read.
Update: What size shall we use for the country flag in tag wiki.
Those are sponsored tags (FAQ: What do icons on the tags mean?). Putting icons on unsponsored tags has been requested before and declined.
OTOH, it's fine to add flags to the tag wikis for countries, so please do so!
More info about sponsored tags can be found here.