[jchw]

There is no license addendum. It is explicitly stated that they are asking you to respect this rule.

> The code is released under the BSD-3 License (see LICENSE.txt for details), but we also ask that users respect the following:

The license is in LICENSE.txt and that statement seems to unambiguously confirm that LICENSE.txt is the beginning and end of actual legal obligations.

It is not uncommon for FOSS projects to make requests without legal contract about how users use software. In this case it may simply be SalesForce trying to preliminarily distance themselves from malicious actors, with knowledge that the license would be useless if it attempted to give these rules teeth.