What does "per developer" mean when buying the license for pro version

Hi, I am planning to purchase core UI pro team bundle. I am wondering what does price per developer mean, can anyone help.

My company needs an answer to this as well, please.

  1. Is there a way to transfer licenses between developers?
    Developers A and B have licenses. Developer B quit, and we hired Developer C. Can Dev B’s license be transferred over?

  2. Would there have to be any separate license for build agents, such as Jenkins, CodeBuild, etc?