This repository contains the RA Plus mod, which is a sub-mod that technically depends on the Red Alert mod of the OpenRA engine, yet is offered as a standalone.
The mod is being developed here with infrequent updates.
The OpenRA engine and SDK scripts are made available under the GPLv3 license, and any executable code developed by a mod and loaded by the engine (i.e. custom mod DLLs, lua scripts) must be released under a compatible license. Your mod data files (artwork, sound files, yaml, etc) are not part of your mod's source code, so your are free to distribute these assets under different terms (e.g. allowing redistribution in unmodified form, but not for use in other works).