What does Siege Combat do in AoE3?

Elite Ram: hit points +15%, damage +15%; Light Cannon: hit points +15%, damage +15%; Elite Mantlet: hit points +15%, damage +15%. The game says: "All Haudenosaunee Siege weapons get increased damage and hitpoints."

Home City card

Siege Combat

Siege Combat (tech ID HCXPSiegeCombat) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 1 civilization, sent from the Fortress Age. Effect: Elite Ram: hit points +15%, damage +15%; Light Cannon: hit points +15%, damage +15%; Elite Mantlet: hit points +15%, damage +15%.

Quick answers (3)

Which civilizations have the Siege Combat card?: Haudenosaunee.
What does Siege Combat do in AoE3?: Elite Ram: hit points +15%, damage +15%; Light Cannon: hit points +15%, damage +15%; Elite Mantlet: hit points +15%, damage +15%. The game says: "All Haudenosaunee Siege weapons get increased damage and hitpoints."
What is the tech ID of Siege Combat?: HCXPSiegeCombat.

All Haudenosaunee Siege weapons get increased damage and hitpoints.

What it does

Elite Ram: hit points +15%, damage +15%
Light Cannon: hit points +15%, damage +15%
Elite Mantlet: hit points +15%, damage +15%

Cost: 1
Sent from: III
Times it can be sent: 1
Game ID: HCXPSiegeCombat

In these decks

HaudenosauneeIII×1

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