What does Melee Infantry Combat do in AoE3?

Plumed Spearman: hit points +15%, damage +15%; War Chief: hit points +15%, damage +15%; Maceman: hit points +15%, damage +15%; Chimu Runner: hit points +15%, damage +15%. The game says: "Plumed Spearmen, Macemen, War Chief and Chimu Runners attack and hitpoints increased."

Home City card

Melee Infantry Combat

Melee Infantry Combat (tech ID DEHCMeleeInfCombatInca) is a Home City card in AoE3: Definitive Edition 100.19.18309, in the decks of 1 civilization, sent from the Fortress Age. Effect: Plumed Spearman: hit points +15%, damage +15%; War Chief: hit points +15%, damage +15%; Maceman: hit points +15%, damage +15%; Chimu Runner: hit points +15%, damage +15%.

Quick answers (3)

Which civilizations have the Melee Infantry Combat card?: Inca.
What does Melee Infantry Combat do in AoE3?: Plumed Spearman: hit points +15%, damage +15%; War Chief: hit points +15%, damage +15%; Maceman: hit points +15%, damage +15%; Chimu Runner: hit points +15%, damage +15%. The game says: "Plumed Spearmen, Macemen, War Chief and Chimu Runners attack and hitpoints increased."
What is the tech ID of Melee Infantry Combat?: DEHCMeleeInfCombatInca.

Plumed Spearmen, Macemen, War Chief and Chimu Runners attack and hitpoints increased.

What it does

Plumed Spearman: hit points +15%, damage +15%
War Chief: hit points +15%, damage +15%
Maceman: hit points +15%, damage +15%
Chimu Runner: hit points +15%, damage +15%

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

In these decks

IncaIII×1

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