Doing what?
Wasn't it obvious they were building a Tachyon Communication Relay Station?
"Scientific investigation. We are building a stellar observatory here to monitor this star's changes over the long term and provide data for certain studies related to stellar evolution," the Silver Heart Civilization said off the cuff, lying without the slightest hesitation.
To their surprise, the other party actually believed it. "Oh, so that's it. But how come you don't know the communication language of the Saidesi Empire? If we didn't have a communication expert aboard our ship, we really wouldn't have been able to decipher your language. Oh, right, where are you from? What species are you? Don't you know you need to file a report before entering imperial territory?"
Empire. Species. Imperial territory. File a report.
Seeing this key information, Great Voyage Headquarters fell into deep thought. They thought it might have been a translation error, but after confirming it again and again, they discovered that the other party really was asking about species, not civilization, and really had said entering imperial territory, not entering the territory of such-and-such civilization.
On top of that, the other party did not seem particularly guarded. It looked like the situation in the M87 Nebula was a little different.
"We come from the Galactic Great Voyage Organization. Carbon-based life. As for the report you mentioned, we truly did not know about it." The Silver Heart Civilization did not give its own great name, but instead communicated with them in the name of the Great Voyage Organization.
And during the conversation, they discovered that those thirteen spaceships were actually charging straight toward the star system they were in without slowing down at all.
If the ones taking such action had been warships, that would have been no different from a deliberate