It'd be very useful to have API for changing state of `_effects_enabled`.
This is the only way of changing it I'm aware of.
The problem with it is not only fact that the game window needs to be focused (since SendMessage doesn't work, you have to use SendInput), it also requires to have specific key bind set, which is very inconvenient to control from add-on. It doesn't let you set specific state (true / false) but instead toggles it, which leaves no other choice for add-on developer than trusting user that variable's state is either of these, if we want to set it to the other.
Another useful API would be ability to select current preset with a function, and ability to dynamically create presets from an add-on to render selected effects.