Where does MELPA's package versions come from?

[Stefan Monnier]

E.g. at https://stable.melpa.org/#/camlhttps://github.com/ocaml/caml-mode

I see that the package is released as version 4.7.1 but I can't figure
out where this info comes from: the recipe is

    (caml :repo "ocaml/caml-mode" :fetcher github)

and the code at https://github.com/ocaml/caml-mode doesn't seem to say
"4.7.1" anywhere either.

So where does MELPA find the release version number?


        Stefan