DragonTranslations
This is a resource to allow developers to easily add translations with little work on their end. I am aware that there’s a pull request to add translation support into sponge itself via #12243 of the Sponge Api but I don’t know when that will get completed/merged. I made this to use in the meantime while we wait for it.
For developers wanting to use this in their plugin, see the docs under developer use. As a server owner using plugins supporting this, all you have to do is download it and install it onto your server like a regular plugin.