You can search for identifiers within the package.
in-package search v0.2.0
type button =
| Button_Left
| Button_Middle
| Button_Right
| Button_X1
| Button_X2
| Button_X3
| Button_X4
| Button_X5
type pos = int * int
val get_state : unit -> pos * button list
val get_buttons : unit -> button list
val get_pos : unit -> pos
val warp_in_window : Sdlwindow.t -> x:int -> y:int -> unit
val set_relative_mode : enabled:bool -> unit
val show_cursor : toggle:bool -> unit
val cursor_is_shown : unit -> bool
val to_string : button -> string
val of_string : string -> button