How do Build licenses work?

This article explains how a build license works.

SPCAF Build licenses are licensed by the number of servers. A server is a virtual or physical machine running one or more build agents using SPCAF.

e.g. If a build controller has 2 or more build agents on the same machine, one license is sufficient. If the build agent is on a separate machine, a license is required for each machine with a build agent.