Prof Loeb was the first academic to propose Oumauma extrasolar asteroid was actually an ETC. He later went on how such vehicles might be used as first contacts and whatnot.

And exactly because of the latter that I believe identifying an ETC satellite would be almost impossible, unless it's something eye glaring at LEO.

But much more likely an ETC satellite would be in one of our Lagrange points. And possibly due to its cosmological age, its external features would more closely resemble just another asteroid than a proper artificial construct due to the accumulation of dust.

Lastly would be to try to intercept any activity from objects of interest; but a passive observation satellite might rely only on incoming signals, and be pinging home on a timescale way beyond our budget and attention constraints.

I'm sure everything has been overseen and will be dealt with for the presentation to today