You can search for identifiers within the package.
in-package search v0.2.0
server-reason-react.fetch
Fetch.Headers
type t = headers
val make : unit -> 'a Js.Dict.t
val makeWithInit : headersInit -> t
val append : string -> string -> t -> unit
val delete : string -> t -> unit
val get : string -> t -> string option
val has : string -> t -> bool
val set : string -> string -> t -> unit