I'm not the author, but it appears that the green tag is your current time zone, at the time you want to convert from. Initially, this starts as the current time, but it can be adjusted. When you move the green tag, a purple tag is placed to represent the current time instead.
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I'm assuming the green timezone is your current timezone? Perhaps that could be spelled out somewhere.
I'm not the author, but it appears that the green tag is your current time zone, at the time you want to convert from. Initially, this starts as the current time, but it can be adjusted. When you move the green tag, a purple tag is placed to represent the current time instead.