You can search for identifiers within the package.
in-package search v0.2.0
type 'a t = 'a option
exception No_value
val some : 'a -> 'b option
val none : 'a option
val option : none:'a Lazy.t -> some:('b -> 'c) -> 'd option -> 'e
val value_exn : 'a option -> 'b
val value : default:'a -> 'b option -> 'c
val return : 'a -> 'b option
val (>>=) : 'a option -> ('b -> 'c option) -> 'c option
val (>>|) : 'a option -> ('b -> 'c) -> 'd option
val (>>) : 'a option -> 'b option -> 'b option
val (|?) : 'a option -> 'b -> 'c
val (?!) : 'a option -> 'b
module Public : sig ... end