The licence restrictions clause should clarify that no ownership rights are established in the licensed software, and that the licensee must not grant access to unauthorised people.

Usually, a list of prohibited actions (that would imply copying, reproducing or worse, re-engineering of the source code). The prohibition could be as broad as a general prohibition on the licensee to copy the functionality of the software. To the extent that this relates to the licensed software, all such acts should not be the subject of negotiation.