How do we decide to create a Symfony component?

If you observe the evolution of Symfony over time, you may wonder how the core-team decides that a given topic would make a good component? There are already existing libraries for almost everything, so why create new ones? How does Symfony get inspired by other projects and does it happen often? Does the fact that Symfony components are used everywhere bring additional features? How are Symfony dependencies chosen? Or more generally: how does the Symfony project interact with other frameworks and libraries?

During this conference, I propose to study these questions, to help you understand the underlying reasoning. It will be an opportunity to illustrate the famous “package principles” and maybe give you a better idea of how you decide to adopt (or rewrite) such or such dependency.