Vaguely familiar nomads

"Say Lieutenant, I'm noticing a big, and I mean very big signature here on the Deep Space Radars"
"Let's see here... probably the wandering fleet. Nomads, basically, they go around in these massive ships along with a bunch of detachments" The Lieutenant quickly sends important emails to a large amount of other Radar stations. "I've gone on board to one of the library ships once, very impressive sight I'll say. The important thing here is that they always carry around a whole lot of trading material.
"I see, I guess that may be the reason we're just letting them through, right?"
"I mean, there's been a few diplomatic alterations, mostly on routes, but those were long ago, and quite a lot of those altercations went down once we started comparing history books. Something about the probability of the original culture being the same of sorts"
"What, like, the planet?"
"Ah let me find the words to explain it... The original planet died or something, one of the countries there, the one that sent the ship to Laska, was also apparently the one that sent the original nomad ship, they put their entire national library on that ship"
"So they're like, distant familiars? Sounds odd"
"Something like that, our actual cultures ended up being quite different, but eh that's what thousands of years of diffusion will do to one"
"Right, so I guess they're somewhat harmless, to us anyways"
"Yeah, they don't like how stingy we are with our cultural artifacts thought" An email flashes up in the Lieutenant's screen, a list of things to buy along with a list of things approved for sale, after reading through it, the Lieutenant approves of it. "Hey, send this file towards them, here's their contact information"
"Roger"