There are the drafts, but even if final standards were available for free, this kind of knowledge is too fine grained to keep all in head across language revisions.

I bet many ISO committee members aren't able to answer "what are the semantics of this code" with looking into the standard.

And there lies the problem, it is not possible as contractor jumping into a foreign code base to be certain of everything that is going on there.

Now imagine the task of upgrading a codebase to a newer compiler and language version, while assuring everything keeps working the same way.