Only really nice when not CLA is required and every contributor retains their copyright. Ente doesn’t seem to require a CLA.

Otherwise it allows the owner to just take the changes from their contributors and change the license at a later date.

Or other standard archiving formats like WARC.

There also is https://github.com/ArchiveBox/ArchiveBox which looks a bit similar.

It contains only code, no assets or textures.

I mod my games on my PC and sync it to my SteamDeck. I also sync the save files back and fourth, to continue playing on different devices. Mostly non-steam games.

I also sync my eBook collection to my eink reader with syncthing.

Everything is also mirrored to my always-on NAS, so syncing always works.

Environment variables isn’t a concept of just docker, but general native app programming. So look into the docs of your language.