Thank you @BRGEzeHulton!
Thanks to the image of the Epic Game Developer site you attached, I was able to locate the files for the Water System plugin.
However, the bug you mentioned is a concerning issue. I tested it in my own project (UE5.4), and while the project didn’t crash, placing a Lake in the scene only resulted in a black plane with no water effect.
My project uses assets that are not compatible with UE5.5, and I’ve already built quite a bit with UE5.4, so downgrading isn’t an option. I’d like to explore alternative ways to implement water effects.
Again, I really appreciate your advice and the information you shared!