It might shout for help—perhaps it’s facing a long-term existential threat that it hopes other civilizations have surmounted and could advise upon—or at least announce its existence if it knows its end is nigh. It might want to brag about its cultural achievements and high points. It might want to convert others to its religion, or sell information, or simply shout out to try and end a sense of loneliness. There are numerous possibilities.
