>>413368867
Sol is the weather simulation scripts and controller
https://www.racedepartment.com/downloads/sol.24914/
Pure changes the lighting in AC to make brightness and exposure look more realistic, particularly at night. It can be used with or without Sol as Sol still has more weather options. I think it's intended to eventually replace Sol but right now it's Patreon only.
You can find a lot of great mods, maps and tracks on racedepartment. Some only have the full/premium versions on discord or behind various paywalls.
cs.rin.ru has an AC thread for mod piracy.