I would say a part of it is clickbait kind of thing. In the abstract they say that they have investigated currently existing advanced civilization that have mad

I would say a part of it is clickbait kind of thing. In the abstract they say that they have investigated currently existing advanced civilization that have made significant advances in harnessing the energy from stars in their Local Group. When you read their entire paper, you realize they have only made strong guesses. Rest of the paper is good enough.