A mod that adds fireflies and various glow-in-the-dark ambient entities to your world.
Please note that even though this video is a showcase of Illuminations, it is possible to achieve a similar result on Forge 1.12 with this mod.
Lumen is an updated Forge 1.12 version of the very popular Illuminations. Since this version is a direct continuation of the original Lumen, this mod and Illuminations are drastically different, and Illuminations features such as player cosmetics and client-only sidedness are not present in this mod.
Can I include this mod in a modpack?
Yes: You can. Go ahead, don't bother asking. Please however provide credit and a link to either the GitHub repository or Curse Forge project page.
Can I use this mod on a vanilla server?
No: Unlike Illuminations, this mod is not client-only, meaning that in order to see fireflies and such, you'll also need the mod to be installed on the server.
If you have any questions, propositions or ideas, please submit them in the Minecraft Curse Forge Project page comment section! Or, you could...