Some things in multiplayer were different than in singleplayer in C&C1. MLRS was available for both factions is one of these things.
https://cnc.fandom.com/wiki/Multiple_La ... rian_Dawn)
However the unit could attack ground and air.
In the Tiberian Dawn mod of openRA go here:
/mods/cnc/weapons/missiles.yaml
/mods/cnc/rules/vehicles.yaml
in vehicles.yaml there is an entry
MLRS:
{...]
Inherits@AUTOTARGET: ^AutoTargetAir
[...]
Armament:
Weapon: Patriot
LocalOffset: 0,-171,0, 0,171,0
[...]
copy the 3 Lines of Armament and paste directly below Armament and change "Weapon: Patriot" to "Weapon: Patriot.AG", change "Armament" to "Armament@primary" and "Armament@secondary". Also change ^AutoTargetAir to Inherits@AUTOTARGET: ^AutoTargetAll
in missiles.yaml:
find the entry
Patriot:
[...]
copy it and paste directly below and change it to this (you can delete all other lines or keep them if you want to change something, I also kept spread and damage here since you might want to change this):
Patriot.AG:
Inherits: Patriot
ValidTargets: Ground, Water
Warhead@1Dam: SpreadDamage
Spread: 682
Damage: 5000
ValidTargets: Ground, Water