What does Heavy Fortifications do in AoE3?

Gives: Sacsayhuaman; Gives: Pukaras; Gives: Mighty Tambos; Gives: Strong War Hut. The game says: "Grants free improvements that increase the combat ability of Strongholds, War Huts, and Tambos."

Home City card

Heavy Fortifications

Heavy Fortifications (tech ID DEHCHeavyFortificationsInca) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 1 civilization, sent from the Industrial Age. Effect: Gives: Sacsayhuaman; Gives: Pukaras; Gives: Mighty Tambos; Gives: Strong War Hut.

Quick answers (3)

Which civilizations have the Heavy Fortifications card?: Inca.
What does Heavy Fortifications do in AoE3?: Gives: Sacsayhuaman; Gives: Pukaras; Gives: Mighty Tambos; Gives: Strong War Hut. The game says: "Grants free improvements that increase the combat ability of Strongholds, War Huts, and Tambos."
What is the tech ID of Heavy Fortifications?: DEHCHeavyFortificationsInca.

Grants free improvements that increase the combat ability of Strongholds, War Huts, and Tambos.

What it does

Gives: Sacsayhuaman
Gives: Pukaras
Gives: Mighty Tambos
Gives: Strong War Hut
Gives: Mighty War Hut
Gives: Heavy Fixed Guns

Cost: 1250
Sent from: IV
Times it can be sent: 1
Game ID: DEHCHeavyFortificationsInca

In these decks

IncaIV×1

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