You can search for identifiers within the package.
in-package search v0.2.0
select.ml
1 2 # 1 "lib/picos_threaded/select.some.ml" let cancel_after = Picos_select.cancel_after
1 2
# 1 "lib/picos_threaded/select.some.ml" let cancel_after = Picos_select.cancel_after