What's with the Petrov? The Petrov or Russian opening is seldom seen these days:

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1. e4 e5 2. Nf3 Nf6


Why? Is it fully refuted? Or merely uncomfortable for Black?
There is nothing wrong with the Petroff and it is still used regularly at the highest levels. If it is less popular than it used to be (and I'd have to check the data before claiming that), then that would likely be because it is usually played when Black is trying to make a draw, and these days the Berlin variation of the Ruy Lopez is the most popular way to try to achieve a draw against 1.e4.