Ahh, just finished a quest - searching for hidden flags scattered all over the Arena area. It was tough but I managed to find most of the them. The idea is "green" as these flags were designed from old clothes and fabrics, kind of "garbage".
I couldn’t find some of them as they were not hanged out in the windows and this places were closed for public. So, if I find more of them in the nearest future - I will keep you updated!