I could not glean from the arxiv paper how far away these anomalous stars were from Earth.
Assuming c is a hard limit, the ETI would have to be roughly 50 LY away to catch our first signals and send a beacon signal.
If instead they observed Earth as a possible life-bearing planet, which could have been made thousands or millions of years ago, then disregard above paragraph.
Or maybe they are just generating signals in more than one direction.
Or maybe our interpretation of the anomalies needs adjustment.
"The Breakthrough team don’t seem that excited about Borra’s findings. They’ve already poured cold water on it, trotting out the old axiom that “Extraordinary claims require extraordinary evidence” in a statement on Borra’s paper. They also give Borra’s findings a score of 0 to 1 on the Rio Scale. The Rio Scale is something used by the international SETI community to rank detections of phenomena that could indicate advanced life beyond Earth. A rating of 0 to 1 means its insignificant.
Assuming c is a hard limit, the ETI would have to be roughly 50 LY away to catch our first signals and send a beacon signal.
If instead they observed Earth as a possible life-bearing planet, which could have been made thousands or millions of years ago, then disregard above paragraph.
Or maybe they are just generating signals in more than one direction.
Or maybe our interpretation of the anomalies needs adjustment.