You can search for identifiers within the package.
in-package search v0.2.0
val on : unit -> unit
val off : unit -> unit
val set : int -> unit
val level : unit -> int
type flag
val get_flag : string -> flag
val set_flag : flag -> unit
val flag_list : unit -> string list
val printf : ?level:int -> ?flag:flag -> ('a, unit, string, unit) format4 -> 'a
val put : ?level:int -> ?flag:flag -> ('a, unit, string, unit) format4 -> 'a
val print_string : ?level:int -> ?flag:flag -> string -> unit
val exe : ?level:int -> ?flag:flag -> (unit -> unit) -> unit