You can search for identifiers within the package.
in-package search v0.2.0
type tok = Parse_info.t
type 'a wrap = 'a * tok
type tree =
| Parens of tok * (trees, tok) Common.either list * tok
| Braces of tok * trees * tok
| Angle of tok * trees * tok
| Bracket of tok * trees * tok
| Metavar of string wrap
| Dots of tok
| Tok of string wrap
and trees = tree list
val is_metavar : string -> bool