What does Oldenburg Kings do in AoE3?

Gives: de Map Is European; Ships 1 Native Embassy Travois; Native Embassy: becomes available; Northern Musketeer: becomes available, population set to 1. The game says: "Ships 1 Royal Embassy in which the House of Oldenburg grants access to its royal units, upgrades, and technologies. Oldenburg units now cost population when acquired from the Royal Embassy or the home"

Home City card

Oldenburg Kings

Oldenburg Kings (tech ID DEHCOldenburgKings) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 1 civilization, sent from the Discovery Age. Effect: Gives: de Map Is European; Ships 1 Native Embassy Travois; Native Embassy: becomes available; Northern Musketeer: becomes available, population set to 1.

Quick answers (3)

Which civilizations have the Oldenburg Kings card?: Danes.
What does Oldenburg Kings do in AoE3?: Gives: de Map Is European; Ships 1 Native Embassy Travois; Native Embassy: becomes available; Northern Musketeer: becomes available, population set to 1. The game says: "Ships 1 Royal Embassy in which the House of Oldenburg grants access to its royal units, upgrades, and technologies. Oldenburg units now cost population when acquired from the Royal Embassy or the home"
What is the tech ID of Oldenburg Kings?: DEHCOldenburgKings.

Ships 1 Royal Embassy in which the House of Oldenburg grants access to its royal units, upgrades, and technologies. Oldenburg units now cost population when acquired from the Royal Embassy or the home city.

What it does

Gives: de Map Is European
Ships 1 Native Embassy Travois(unit)
Native Embassy: becomes available
Northern Musketeer: becomes available, population set to 1
Royal Huntsman: becomes available, population set to 2
Royal Hunter: population set to 1
Makes researchable: Veteran Oldenburgs
Makes researchable: Royal Guard Oldenburgs
Makes researchable: League of Armed Neutrality
Makes researchable: Hunting Expeditions
Makes researchable: Kalthoff Repeaters
Makes researchable: Baltic Sea Trade
Makes researchable: DE Oldenburg Kings Armed Neutrality Shadow

13 further effects (interface, visuals or AI) not listed.

What it hands over

1 × Native Embassy Travoisno train cost

Total ≈ 0 resources — units at their train cost, crates and animals at what they hold.

Cost: 1
Sent from: I
Times it can be sent: 1
Game ID: DEHCOldenburgKings

In these decks

DanesI×1

Source: techtreey.xml and the Home City files, AoE3: DE 100.19.18309 (build 25040513).