https://github.com/storm-devs/storm-engine -> GPL 3 if the source code is mainly based on the source code of the storm engine then the GPL license requires to publish it.
Maelstrom is derived from 2010 code source and is not GPL. Just because that site and those devs took similar source and in 2020 decided to put it under GPL and did some mods, that GPL does not retroactively apply. Nothing from Maelstrom is taken from their code offering.
