/jp/ - Otaku Culture

I have a question regarding modding.
Let's say i want to add a weather condition or a celestial event (similar to shooting star, rainbow, etc.) and make it modify the mood of active 2hus, how is all of this handled ingame?
I took some time to read the modding section on the wiki but it only explains what functions the engine itself has, is there some kind of documentation on the game section?

All i've learned from playing around with moon phases is that most of the UI information is stored in 口上・メッセージ関連/INFO, celestial/weather events have to be added in multiple places to have effect and shooting star is a restored event that is stored in translation/addition/add_misc(??) and is called from 日時天候管理 in base ERB folder (???)
Yet another modding rabbit hole

what's the appeal of reimu?