What does TEAM Coehorn Mortars do in AoE3?

Mortar: damage +20%; Morutaru: damage +20%; Hand Mortar: damage +20%; Mortar: damage +20%. The game says: "TEAM Mortar attack increased. For Chinese and Japanese allies, Hand Mortar and Morutaru attack increased."

Home City card

TEAM Coehorn Mortars

TEAM Coehorn Mortars (tech ID HCMortarsDamageDutchTeam) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 1 civilization, sent from the Industrial Age. Effect: Mortar: damage +20%; Morutaru: damage +20%; Hand Mortar: damage +20%; Mortar: damage +20%.

Quick answers (3)

Which civilizations have the TEAM Coehorn Mortars card?: Dutch.
What does TEAM Coehorn Mortars do in AoE3?: Mortar: damage +20%; Morutaru: damage +20%; Hand Mortar: damage +20%; Mortar: damage +20%. The game says: "TEAM Mortar attack increased. For Chinese and Japanese allies, Hand Mortar and Morutaru attack increased."
What is the tech ID of TEAM Coehorn Mortars?: HCMortarsDamageDutchTeam.

TEAM Mortar attack increased. For Chinese and Japanese allies, Hand Mortar and Morutaru attack increased.

What it does

Mortar: damage +20%
Morutaru: damage +20%
Hand Mortar: damage +20%
Mortar: damage +20%
Grenadier: damage (Mortar) +20%
Sebastopol Mortar: damage +20%

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

In these decks

DutchIV×1

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