Hi there, I'm posting here because it's more underground compared to Reddit (since I think that the dev wouldn't like it to get mainstream attention).
There is an open-source WC3 engine called Warsmash (made using LibGDX): https://github.com/Retera/WarsmashModEngine
( Discord server: https://discord.com/invite/ucjftZ7x7H )
I thought I might share it here, if anyone is interested in participating in its development. There isn't a Flatpak version yet and it also misses some features e.g.
I don't think so, but it sounded like he isn't sure about the correct legal license because he said once that he may need to change the license to GPL. If you wanna, you can join the Discord server (he is pretty active there) and talk with him about the proper licensing of his project.
No because luckily open source licensing does not care if a maintainer is too lazy to read a few lines of MIT License. I'm not a native speaker and I understand the MIT License just fine.