...It is merely interfaces that describe the components of a HTTP Factory. The installable package and implementations are listed on Packagist. PSR-7 did not include a recommendation on how to create HTTP objects, which leads to difficulties when needing to create new HTTP objects within components that are not tied to a specific implementation of PSR-7. An HTTP factory is a method by which a new HTTP object, as defined by PSR-7, is created. HTTP factories MUST implement these interfaces for each object type that is provided by the package.