Tagging this kind of software as commercial (or something) would allow to save some time... Here is (below) essential - but unfortunately not quite easy to find - licensing information:
"Seats determine the maximum number of workers that can use the software at the same time."
In the final step of the installer you are given the opportunity to introduce yourself to the Cerb development team in exchange for a free 3 seat (simultaneous workers) license to help you get started. There are no strings attached. This free license provides full functionality, with no expiration, but it does not include future updates. We hope that you find the software useful, and we’re looking forward to growing along with you.
If you choose not to register your copy of Cerb then the software will default to Free Mode which is limited to a single seat but has no other restrictions.
Complete the short survey in exchange for your free license and then click the Register button."