Don't Download Unless You Are A Developer

Putting this in your Mods folder will do nothing.

If you are a Developer

The example projects on GitLab contain all the basics you need to get started using the API.
https://gitlab.com/jeseibel/distant-horizons-api-example

Additional resources

API JavaDocs
https://jeseibel.gitlab.io/minecraft-lod-mod/

Developer Wiki
https://gitlab.com/jeseibel/distant-horizons-core/-/wikis/home

Discord
In case you have any questions or issues not addressed in the above two documents.
https://discord.gg/xAB8G4cENx

Issues
If you find any bugs or want to request a new feature, for the API, please use the main Distant Horizons GitLab issue page.
https://gitlab.com/jeseibel/minecraft-lod-mod/-/issues