Here is a list of all documented variables with links to the class documentation for each member:

actionNegative : utils::PlayerInput::Listener
actionPositive : utils::PlayerInput::Listener
callable : utils::PlayerInput::Listener
device : utils::PlayerInput
first_boot_level : utils::GameRoot3D
game_mode : utils::GameRoot3D
game_mode_prototype : utils::Level3D
game_state : utils::GameRoot3D
game_state_prototype : utils::GameRoot3D
isMouseEvent : utils::PlayerInput::Listener
isPrimary : utils::PlayerInput
lastCached : utils::PlayerInput::Listener
lastMouseMotion : utils::PlayerInput
levels : utils::GameRoot3D
listeners : utils::PlayerInput
next_player_id : utils::GameRoot3D
player_scene : utils::GameMode
players : utils::GameRoot3D
primaryExists : utils::PlayerInput
rng : utils::GameRoot3D
spawn_points : utils::GameRoot3D