Which civilizations have the Extensive Fortifications card?

British, Dutch, French, Ottomans, Spanish, Swedes, Italians, Maltese and Danes.

What does Extensive Fortifications do in AoE3?

Outpost: build limit +100%; Frontier Fortification: hit points +25%; Walls: hit points +25%; Fort: hit points +25%. The game says: "Enables you to construct twice as many Outposts and increases the hitpoints of ALL fortifications!"

Home City card

Extensive Fortifications

Extensive Fortifications (tech ID DEHCExtensiveFortificationsEuropean) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 9 civilizations, sent from the Colonial Age. Effect: Outpost: build limit +100%; Frontier Fortification: hit points +25%; Walls: hit points +25%; Fort: hit points +25%.

Quick answers (3)

Which civilizations have the Extensive Fortifications card?: British, Dutch, French, Ottomans, Spanish, Swedes, Italians, Maltese and Danes.
What does Extensive Fortifications do in AoE3?: Outpost: build limit +100%; Frontier Fortification: hit points +25%; Walls: hit points +25%; Fort: hit points +25%. The game says: "Enables you to construct twice as many Outposts and increases the hitpoints of ALL fortifications!"
What is the tech ID of Extensive Fortifications?: DEHCExtensiveFortificationsEuropean.