Which civilizations have the Danubian Principalities card?

Ottomans, Russians and Italians.

What does Danubian Principalities do in AoE3?

Native Embassy: becomes available; Ships 1 Native Embassy Travois; Gives: de Map Is European; Evzone: becomes available, population +1, build limit set to -1. The game says: "The influential Houses of Phanar grant access to their units, upgrades, and technologies. Unless trained from a settlement, Phanariote units now cost population, but can be trained from a variety of b"

Home City card

Danubian Principalities

Danubian Principalities (tech ID DEHCREVPhanariotes) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 3 civilizations, sent from the Colonial Age. Effect: Native Embassy: becomes available; Ships 1 Native Embassy Travois; Gives: de Map Is European; Evzone: becomes available, population +1, build limit set to -1.

Quick answers (3)

Which civilizations have the Danubian Principalities card?: Ottomans, Russians and Italians.
What does Danubian Principalities do in AoE3?: Native Embassy: becomes available; Ships 1 Native Embassy Travois; Gives: de Map Is European; Evzone: becomes available, population +1, build limit set to -1. The game says: "The influential Houses of Phanar grant access to their units, upgrades, and technologies. Unless trained from a settlement, Phanariote units now cost population, but can be trained from a variety of b"
What is the tech ID of Danubian Principalities?: DEHCREVPhanariotes.

The influential Houses of Phanar grant access to their units, upgrades, and technologies. Unless trained from a settlement, Phanariote units now cost population, but can be trained from a variety of buildings without limit.