You can search for identifiers within the package.
in-package search v0.2.0
type storage = Stdlib.Bytes.t
val of_key : secret key -> storage
val to_key : storage -> secret key
val of_nonce : nonce -> storage
val to_nonce : storage -> nonce
val stream : secret key -> int -> nonce -> storage
val stream_xor : secret key -> storage -> nonce -> storage